ftdi.c

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/***************************************************************************
                          ftdi.c  -  description
                             -------------------
    begin                : Fri Apr 4 2003
    copyright            : (C) 2003-2013 by Intra2net AG and the libftdi developers
    email                : opensource@intra2net.com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU Lesser General Public License           *
 *   version 2.1 as published by the Free Software Foundation;             *
 *                                                                         *
 ***************************************************************************/

/* @{ */

#include <libusb.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>

#include "ftdi_i.h"
#include "ftdi.h"
#include "ftdi_version_i.h"

#define ftdi_error_return(code, str) do {  \
        if ( ftdi )                        \
            ftdi->error_str = str;         \
        else                               \
            fprintf(stderr, str);          \
        return code;                       \
   } while(0);

#define ftdi_error_return_free_device_list(code, str, devs) do {    \
        libusb_free_device_list(devs,1);   \
        ftdi->error_str = str;             \
        return code;                       \
   } while(0);


static void ftdi_usb_close_internal (struct ftdi_context *ftdi)
{
    if (ftdi && ftdi->usb_dev)
    {
        libusb_close (ftdi->usb_dev);
        ftdi->usb_dev = NULL;
        if(ftdi->eeprom)
            ftdi->eeprom->initialized_for_connected_device = 0;
    }
}

int ftdi_init(struct ftdi_context *ftdi)
{
    struct ftdi_eeprom* eeprom = (struct ftdi_eeprom *)malloc(sizeof(struct ftdi_eeprom));
    ftdi->usb_ctx = NULL;
    ftdi->usb_dev = NULL;
    ftdi->usb_read_timeout = 5000;
    ftdi->usb_write_timeout = 5000;

    ftdi->type = TYPE_BM;    /* chip type */
    ftdi->baudrate = -1;
    ftdi->bitbang_enabled = 0;  /* 0: normal mode 1: any of the bitbang modes enabled */

    ftdi->readbuffer = NULL;
    ftdi->readbuffer_offset = 0;
    ftdi->readbuffer_remaining = 0;
    ftdi->writebuffer_chunksize = 4096;
    ftdi->max_packet_size = 0;
    ftdi->error_str = NULL;
    ftdi->module_detach_mode = AUTO_DETACH_SIO_MODULE;

    if (libusb_init(&ftdi->usb_ctx) < 0)
        ftdi_error_return(-3, "libusb_init() failed");

    ftdi_set_interface(ftdi, INTERFACE_ANY);
    ftdi->bitbang_mode = 1; /* when bitbang is enabled this holds the number of the mode  */

    if (eeprom == 0)
        ftdi_error_return(-2, "Can't malloc struct ftdi_eeprom");
    memset(eeprom, 0, sizeof(struct ftdi_eeprom));
    ftdi->eeprom = eeprom;

    /* All fine. Now allocate the readbuffer */
    return ftdi_read_data_set_chunksize(ftdi, 4096);
}

struct ftdi_context *ftdi_new(void)
{
    struct ftdi_context * ftdi = (struct ftdi_context *)malloc(sizeof(struct ftdi_context));

    if (ftdi == NULL)
    {
        return NULL;
    }

    if (ftdi_init(ftdi) != 0)
    {
        free(ftdi);
        return NULL;
    }

    return ftdi;
}

int ftdi_set_interface(struct ftdi_context *ftdi, enum ftdi_interface interface)
{
    if (ftdi == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (ftdi->usb_dev != NULL)
    {
        int check_interface = interface;
        if (check_interface == INTERFACE_ANY)
            check_interface = INTERFACE_A;

        if (ftdi->index != check_interface)
            ftdi_error_return(-3, "Interface can not be changed on an already open device");
    }

    switch (interface)
    {
        case INTERFACE_ANY:
        case INTERFACE_A:
            ftdi->interface = 0;
            ftdi->index     = INTERFACE_A;
            ftdi->in_ep     = 0x02;
            ftdi->out_ep    = 0x81;
            break;
        case INTERFACE_B:
            ftdi->interface = 1;
            ftdi->index     = INTERFACE_B;
            ftdi->in_ep     = 0x04;
            ftdi->out_ep    = 0x83;
            break;
        case INTERFACE_C:
            ftdi->interface = 2;
            ftdi->index     = INTERFACE_C;
            ftdi->in_ep     = 0x06;
            ftdi->out_ep    = 0x85;
            break;
        case INTERFACE_D:
            ftdi->interface = 3;
            ftdi->index     = INTERFACE_D;
            ftdi->in_ep     = 0x08;
            ftdi->out_ep    = 0x87;
            break;
        default:
            ftdi_error_return(-1, "Unknown interface");
    }
    return 0;
}

void ftdi_deinit(struct ftdi_context *ftdi)
{
    if (ftdi == NULL)
        return;

    ftdi_usb_close_internal (ftdi);

    if (ftdi->readbuffer != NULL)
    {
        free(ftdi->readbuffer);
        ftdi->readbuffer = NULL;
    }

    if (ftdi->eeprom != NULL)
    {
        if (ftdi->eeprom->manufacturer != 0)
        {
            free(ftdi->eeprom->manufacturer);
            ftdi->eeprom->manufacturer = 0;
        }
        if (ftdi->eeprom->product != 0)
        {
            free(ftdi->eeprom->product);
            ftdi->eeprom->product = 0;
        }
        if (ftdi->eeprom->serial != 0)
        {
            free(ftdi->eeprom->serial);
            ftdi->eeprom->serial = 0;
        }
        free(ftdi->eeprom);
        ftdi->eeprom = NULL;
    }

    if (ftdi->usb_ctx)
    {
        libusb_exit(ftdi->usb_ctx);
        ftdi->usb_ctx = NULL;
    }
}

void ftdi_free(struct ftdi_context *ftdi)
{
    ftdi_deinit(ftdi);
    free(ftdi);
}

void ftdi_set_usbdev (struct ftdi_context *ftdi, libusb_device_handle *usb)
{
    if (ftdi == NULL)
        return;

    ftdi->usb_dev = usb;
}

struct ftdi_version_info ftdi_get_library_version()
{
    struct ftdi_version_info ver;

    ver.major = FTDI_MAJOR_VERSION;
    ver.minor = FTDI_MINOR_VERSION;
    ver.micro = FTDI_MICRO_VERSION;
    ver.version_str = FTDI_VERSION_STRING;
    ver.snapshot_str = FTDI_SNAPSHOT_VERSION;

    return ver;
}

int ftdi_usb_find_all(struct ftdi_context *ftdi, struct ftdi_device_list **devlist, int vendor, int product)
{
    struct ftdi_device_list **curdev;
    libusb_device *dev;
    libusb_device **devs;
    int count = 0;
    int i = 0;

    if (libusb_get_device_list(ftdi->usb_ctx, &devs) < 0)
        ftdi_error_return(-5, "libusb_get_device_list() failed");

    curdev = devlist;
    *curdev = NULL;

    while ((dev = devs[i++]) != NULL)
    {
        struct libusb_device_descriptor desc;

        if (libusb_get_device_descriptor(dev, &desc) < 0)
            ftdi_error_return_free_device_list(-6, "libusb_get_device_descriptor() failed", devs);

        if (((vendor != 0 && product != 0) && 
             desc.idVendor == vendor && desc.idProduct == product) ||
            ((vendor == 0 && product == 0) && 
             (desc.idVendor == 0x403) && (desc.idProduct == 0x6001 || desc.idProduct == 0x6010
                                          || desc.idProduct == 0x6011 || desc.idProduct == 0x6014)))
        {
            *curdev = (struct ftdi_device_list*)malloc(sizeof(struct ftdi_device_list));
            if (!*curdev)
                ftdi_error_return_free_device_list(-3, "out of memory", devs);

            (*curdev)->next = NULL;
            (*curdev)->dev = dev;
            libusb_ref_device(dev);
            curdev = &(*curdev)->next;
            count++;
        }
    }
    libusb_free_device_list(devs,1);
    return count;
}

void ftdi_list_free(struct ftdi_device_list **devlist)
{
    struct ftdi_device_list *curdev, *next;

    for (curdev = *devlist; curdev != NULL;)
    {
        next = curdev->next;
        libusb_unref_device(curdev->dev);
        free(curdev);
        curdev = next;
    }

    *devlist = NULL;
}

void ftdi_list_free2(struct ftdi_device_list *devlist)
{
    ftdi_list_free(&devlist);
}

int ftdi_usb_get_strings(struct ftdi_context * ftdi, struct libusb_device * dev,
                         char * manufacturer, int mnf_len, char * description, int desc_len, char * serial, int serial_len)
{
    struct libusb_device_descriptor desc;

    if ((ftdi==NULL) || (dev==NULL))
        return -1;

    if (libusb_open(dev, &ftdi->usb_dev) < 0)
        ftdi_error_return(-4, "libusb_open() failed");

    if (libusb_get_device_descriptor(dev, &desc) < 0)
        ftdi_error_return(-11, "libusb_get_device_descriptor() failed");

    if (manufacturer != NULL)
    {
        if (libusb_get_string_descriptor_ascii(ftdi->usb_dev, desc.iManufacturer, (unsigned char *)manufacturer, mnf_len) < 0)
        {
            ftdi_usb_close_internal (ftdi);
            ftdi_error_return(-7, "libusb_get_string_descriptor_ascii() failed");
        }
    }

    if (description != NULL)
    {
        if (libusb_get_string_descriptor_ascii(ftdi->usb_dev, desc.iProduct, (unsigned char *)description, desc_len) < 0)
        {
            ftdi_usb_close_internal (ftdi);
            ftdi_error_return(-8, "libusb_get_string_descriptor_ascii() failed");
        }
    }

    if (serial != NULL)
    {
        if (libusb_get_string_descriptor_ascii(ftdi->usb_dev, desc.iSerialNumber, (unsigned char *)serial, serial_len) < 0)
        {
            ftdi_usb_close_internal (ftdi);
            ftdi_error_return(-9, "libusb_get_string_descriptor_ascii() failed");
        }
    }

    ftdi_usb_close_internal (ftdi);

    return 0;
}

static unsigned int _ftdi_determine_max_packet_size(struct ftdi_context *ftdi, libusb_device *dev)
{
    struct libusb_device_descriptor desc;
    struct libusb_config_descriptor *config0;
    unsigned int packet_size;

    // Sanity check
    if (ftdi == NULL || dev == NULL)
        return 64;

    // Determine maximum packet size. Init with default value.
    // New hi-speed devices from FTDI use a packet size of 512 bytes
    // but could be connected to a normal speed USB hub -> 64 bytes packet size.
    if (ftdi->type == TYPE_2232H || ftdi->type == TYPE_4232H || ftdi->type == TYPE_232H )
        packet_size = 512;
    else
        packet_size = 64;

    if (libusb_get_device_descriptor(dev, &desc) < 0)
        return packet_size;

    if (libusb_get_config_descriptor(dev, 0, &config0) < 0)
        return packet_size;

    if (desc.bNumConfigurations > 0)
    {
        if (ftdi->interface < config0->bNumInterfaces)
        {
            struct libusb_interface interface = config0->interface[ftdi->interface];
            if (interface.num_altsetting > 0)
            {
                struct libusb_interface_descriptor descriptor = interface.altsetting[0];
                if (descriptor.bNumEndpoints > 0)
                {
                    packet_size = descriptor.endpoint[0].wMaxPacketSize;
                }
            }
        }
    }

    libusb_free_config_descriptor (config0);
    return packet_size;
}

int ftdi_usb_open_dev(struct ftdi_context *ftdi, libusb_device *dev)
{
    struct libusb_device_descriptor desc;
    struct libusb_config_descriptor *config0;
    int cfg, cfg0, detach_errno = 0;

    if (ftdi == NULL)
        ftdi_error_return(-8, "ftdi context invalid");

    if (libusb_open(dev, &ftdi->usb_dev) < 0)
        ftdi_error_return(-4, "libusb_open() failed");

    if (libusb_get_device_descriptor(dev, &desc) < 0)
        ftdi_error_return(-9, "libusb_get_device_descriptor() failed");

    if (libusb_get_config_descriptor(dev, 0, &config0) < 0)
        ftdi_error_return(-10, "libusb_get_config_descriptor() failed");
    cfg0 = config0->bConfigurationValue;
    libusb_free_config_descriptor (config0);

    // Try to detach ftdi_sio kernel module.
    //
    // The return code is kept in a separate variable and only parsed
    // if usb_set_configuration() or usb_claim_interface() fails as the
    // detach operation might be denied and everything still works fine.
    // Likely scenario is a static ftdi_sio kernel module.
    if (ftdi->module_detach_mode == AUTO_DETACH_SIO_MODULE)
    {
        if (libusb_detach_kernel_driver(ftdi->usb_dev, ftdi->interface) !=0)
            detach_errno = errno;
    }

    if (libusb_get_configuration (ftdi->usb_dev, &cfg) < 0)
        ftdi_error_return(-12, "libusb_get_configuration () failed");
    // set configuration (needed especially for windows)
    // tolerate EBUSY: one device with one configuration, but two interfaces
    //    and libftdi sessions to both interfaces (e.g. FT2232)
    if (desc.bNumConfigurations > 0 && cfg != cfg0)
    {
        if (libusb_set_configuration(ftdi->usb_dev, cfg0) < 0)
        {
            ftdi_usb_close_internal (ftdi);
            if (detach_errno == EPERM)
            {
                ftdi_error_return(-8, "inappropriate permissions on device!");
            }
            else
            {
                ftdi_error_return(-3, "unable to set usb configuration. Make sure the default FTDI driver is not in use");
            }
        }
    }

    if (libusb_claim_interface(ftdi->usb_dev, ftdi->interface) < 0)
    {
        ftdi_usb_close_internal (ftdi);
        if (detach_errno == EPERM)
        {
            ftdi_error_return(-8, "inappropriate permissions on device!");
        }
        else
        {
            ftdi_error_return(-5, "unable to claim usb device. Make sure the default FTDI driver is not in use");
        }
    }

    if (ftdi_usb_reset (ftdi) != 0)
    {
        ftdi_usb_close_internal (ftdi);
        ftdi_error_return(-6, "ftdi_usb_reset failed");
    }

    // Try to guess chip type
    // Bug in the BM type chips: bcdDevice is 0x200 for serial == 0
    if (desc.bcdDevice == 0x400 || (desc.bcdDevice == 0x200
                                    && desc.iSerialNumber == 0))
        ftdi->type = TYPE_BM;
    else if (desc.bcdDevice == 0x200)
        ftdi->type = TYPE_AM;
    else if (desc.bcdDevice == 0x500)
        ftdi->type = TYPE_2232C;
    else if (desc.bcdDevice == 0x600)
        ftdi->type = TYPE_R;
    else if (desc.bcdDevice == 0x700)
        ftdi->type = TYPE_2232H;
    else if (desc.bcdDevice == 0x800)
        ftdi->type = TYPE_4232H;
    else if (desc.bcdDevice == 0x900)
        ftdi->type = TYPE_232H;

    // Determine maximum packet size
    ftdi->max_packet_size = _ftdi_determine_max_packet_size(ftdi, dev);

    if (ftdi_set_baudrate (ftdi, 9600) != 0)
    {
        ftdi_usb_close_internal (ftdi);
        ftdi_error_return(-7, "set baudrate failed");
    }

    ftdi_error_return(0, "all fine");
}

int ftdi_usb_open(struct ftdi_context *ftdi, int vendor, int product)
{
    return ftdi_usb_open_desc(ftdi, vendor, product, NULL, NULL);
}

int ftdi_usb_open_desc(struct ftdi_context *ftdi, int vendor, int product,
                       const char* description, const char* serial)
{
    return ftdi_usb_open_desc_index(ftdi,vendor,product,description,serial,0);
}

int ftdi_usb_open_desc_index(struct ftdi_context *ftdi, int vendor, int product,
                             const char* description, const char* serial, unsigned int index)
{
    libusb_device *dev;
    libusb_device **devs;
    char string[256];
    int i = 0;

    if (ftdi == NULL)
        ftdi_error_return(-11, "ftdi context invalid");

    if (libusb_get_device_list(ftdi->usb_ctx, &devs) < 0)
        ftdi_error_return(-12, "libusb_get_device_list() failed");

    while ((dev = devs[i++]) != NULL)
    {
        struct libusb_device_descriptor desc;
        int res;

        if (libusb_get_device_descriptor(dev, &desc) < 0)
            ftdi_error_return_free_device_list(-13, "libusb_get_device_descriptor() failed", devs);

        if (desc.idVendor == vendor && desc.idProduct == product)
        {
            if (libusb_open(dev, &ftdi->usb_dev) < 0)
                ftdi_error_return_free_device_list(-4, "usb_open() failed", devs);

            if (description != NULL)
            {
                if (libusb_get_string_descriptor_ascii(ftdi->usb_dev, desc.iProduct, (unsigned char *)string, sizeof(string)) < 0)
                {
                    ftdi_usb_close_internal (ftdi);
                    ftdi_error_return_free_device_list(-8, "unable to fetch product description", devs);
                }
                if (strncmp(string, description, sizeof(string)) != 0)
                {
                    ftdi_usb_close_internal (ftdi);
                    continue;
                }
            }
            if (serial != NULL)
            {
                if (libusb_get_string_descriptor_ascii(ftdi->usb_dev, desc.iSerialNumber, (unsigned char *)string, sizeof(string)) < 0)
                {
                    ftdi_usb_close_internal (ftdi);
                    ftdi_error_return_free_device_list(-9, "unable to fetch serial number", devs);
                }
                if (strncmp(string, serial, sizeof(string)) != 0)
                {
                    ftdi_usb_close_internal (ftdi);
                    continue;
                }
            }

            ftdi_usb_close_internal (ftdi);

            if (index > 0)
            {
                index--;
                continue;
            }

            res = ftdi_usb_open_dev(ftdi, dev);
            libusb_free_device_list(devs,1);
            return res;
        }
    }

    // device not found
    ftdi_error_return_free_device_list(-3, "device not found", devs);
}

int ftdi_usb_open_string(struct ftdi_context *ftdi, const char* description)
{
    if (ftdi == NULL)
        ftdi_error_return(-12, "ftdi context invalid");

    if (description[0] == 0 || description[1] != ':')
        ftdi_error_return(-11, "illegal description format");

    if (description[0] == 'd')
    {
        libusb_device *dev;
        libusb_device **devs;
        unsigned int bus_number, device_address;
        int i = 0;

        if (libusb_get_device_list(ftdi->usb_ctx, &devs) < 0)
            ftdi_error_return(-2, "libusb_get_device_list() failed");

        /* XXX: This doesn't handle symlinks/odd paths/etc... */
        if (sscanf (description + 2, "%u/%u", &bus_number, &device_address) != 2)
            ftdi_error_return_free_device_list(-11, "illegal description format", devs);

        while ((dev = devs[i++]) != NULL)
        {
            int ret;
            if (bus_number == libusb_get_bus_number (dev)
                    && device_address == libusb_get_device_address (dev))
            {
                ret = ftdi_usb_open_dev(ftdi, dev);
                libusb_free_device_list(devs,1);
                return ret;
            }
        }

        // device not found
        ftdi_error_return_free_device_list(-3, "device not found", devs);
    }
    else if (description[0] == 'i' || description[0] == 's')
    {
        unsigned int vendor;
        unsigned int product;
        unsigned int index=0;
        const char *serial=NULL;
        const char *startp, *endp;

        errno=0;
        startp=description+2;
        vendor=strtoul((char*)startp,(char**)&endp,0);
        if (*endp != ':' || endp == startp || errno != 0)
            ftdi_error_return(-11, "illegal description format");

        startp=endp+1;
        product=strtoul((char*)startp,(char**)&endp,0);
        if (endp == startp || errno != 0)
            ftdi_error_return(-11, "illegal description format");

        if (description[0] == 'i' && *endp != 0)
        {
            /* optional index field in i-mode */
            if (*endp != ':')
                ftdi_error_return(-11, "illegal description format");

            startp=endp+1;
            index=strtoul((char*)startp,(char**)&endp,0);
            if (*endp != 0 || endp == startp || errno != 0)
                ftdi_error_return(-11, "illegal description format");
        }
        if (description[0] == 's')
        {
            if (*endp != ':')
                ftdi_error_return(-11, "illegal description format");

            /* rest of the description is the serial */
            serial=endp+1;
        }

        return ftdi_usb_open_desc_index(ftdi, vendor, product, NULL, serial, index);
    }
    else
    {
        ftdi_error_return(-11, "illegal description format");
    }
}

int ftdi_usb_reset(struct ftdi_context *ftdi)
{
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_RESET_REQUEST, SIO_RESET_SIO,
                                ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1,"FTDI reset failed");

    // Invalidate data in the readbuffer
    ftdi->readbuffer_offset = 0;
    ftdi->readbuffer_remaining = 0;

    return 0;
}

int ftdi_usb_purge_rx_buffer(struct ftdi_context *ftdi)
{
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_RESET_REQUEST, SIO_RESET_PURGE_RX,
                                ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "FTDI purge of RX buffer failed");

    // Invalidate data in the readbuffer
    ftdi->readbuffer_offset = 0;
    ftdi->readbuffer_remaining = 0;

    return 0;
}

int ftdi_usb_purge_tx_buffer(struct ftdi_context *ftdi)
{
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_RESET_REQUEST, SIO_RESET_PURGE_TX,
                                ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "FTDI purge of TX buffer failed");

    return 0;
}

int ftdi_usb_purge_buffers(struct ftdi_context *ftdi)
{
    int result;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-3, "USB device unavailable");

    result = ftdi_usb_purge_rx_buffer(ftdi);
    if (result < 0)
        return -1;

    result = ftdi_usb_purge_tx_buffer(ftdi);
    if (result < 0)
        return -2;

    return 0;
}



int ftdi_usb_close(struct ftdi_context *ftdi)
{
    int rtn = 0;

    if (ftdi == NULL)
        ftdi_error_return(-3, "ftdi context invalid");

    if (ftdi->usb_dev != NULL)
        if (libusb_release_interface(ftdi->usb_dev, ftdi->interface) < 0)
            rtn = -1;

    ftdi_usb_close_internal (ftdi);

    return rtn;
}

/*  ftdi_to_clkbits_AM For the AM device, convert a requested baudrate 
                    to encoded divisor and the achievable baudrate
    Function is only used internally
    \internal

    See AN120
   clk/1   -> 0
   clk/1.5 -> 1
   clk/2   -> 2
   From /2, 0.125/ 0.25 and 0.5 steps may be taken
   The fractional part has frac_code encoding
*/
static int ftdi_to_clkbits_AM(int baudrate, unsigned long *encoded_divisor)

{
    static const char frac_code[8] = {0, 3, 2, 4, 1, 5, 6, 7};
    static const char am_adjust_up[8] = {0, 0, 0, 1, 0, 3, 2, 1};
    static const char am_adjust_dn[8] = {0, 0, 0, 1, 0, 1, 2, 3};
    int divisor, best_divisor, best_baud, best_baud_diff;
    divisor = 24000000 / baudrate;
    int i;

    // Round down to supported fraction (AM only)
    divisor -= am_adjust_dn[divisor & 7];

    // Try this divisor and the one above it (because division rounds down)
    best_divisor = 0;
    best_baud = 0;
    best_baud_diff = 0;
    for (i = 0; i < 2; i++)
    {
        int try_divisor = divisor + i;
        int baud_estimate;
        int baud_diff;

        // Round up to supported divisor value
        if (try_divisor <= 8)
        {
            // Round up to minimum supported divisor
            try_divisor = 8;
        }
        else if (divisor < 16)
        {
            // AM doesn't support divisors 9 through 15 inclusive
            try_divisor = 16;
        }
        else
        {
            // Round up to supported fraction (AM only)
            try_divisor += am_adjust_up[try_divisor & 7];
            if (try_divisor > 0x1FFF8)
            {
                // Round down to maximum supported divisor value (for AM)
                try_divisor = 0x1FFF8;
            }
        }
        // Get estimated baud rate (to nearest integer)
        baud_estimate = (24000000 + (try_divisor / 2)) / try_divisor;
        // Get absolute difference from requested baud rate
        if (baud_estimate < baudrate)
        {
            baud_diff = baudrate - baud_estimate;
        }
        else
        {
            baud_diff = baud_estimate - baudrate;
        }
        if (i == 0 || baud_diff < best_baud_diff)
        {
            // Closest to requested baud rate so far
            best_divisor = try_divisor;
            best_baud = baud_estimate;
            best_baud_diff = baud_diff;
            if (baud_diff == 0)
            {
                // Spot on! No point trying
                break;
            }
        }
    }
    // Encode the best divisor value
    *encoded_divisor = (best_divisor >> 3) | (frac_code[best_divisor & 7] << 14);
    // Deal with special cases for encoded value
    if (*encoded_divisor == 1)
    {
        *encoded_divisor = 0;    // 3000000 baud
    }
    else if (*encoded_divisor == 0x4001)
    {
        *encoded_divisor = 1;    // 2000000 baud (BM only)
    }
    return best_baud;
}

/*  ftdi_to_clkbits Convert a requested baudrate for a given system clock  and predivisor
                    to encoded divisor and the achievable baudrate
    Function is only used internally
    \internal

    See AN120
   clk/1   -> 0
   clk/1.5 -> 1
   clk/2   -> 2
   From /2, 0.125 steps may be taken.
   The fractional part has frac_code encoding

   value[13:0] of value is the divisor
   index[9] mean 12 MHz Base(120 MHz/10) rate versus 3 MHz (48 MHz/16) else

   H Type have all features above with
   {index[8],value[15:14]} is the encoded subdivisor

   FT232R, FT2232 and FT232BM have no option for 12 MHz and with 
   {index[0],value[15:14]} is the encoded subdivisor

   AM Type chips have only four fractional subdivisors at value[15:14]
   for subdivisors 0, 0.5, 0.25, 0.125
*/
static int ftdi_to_clkbits(int baudrate, unsigned int clk, int clk_div, unsigned long *encoded_divisor)
{
    static const char frac_code[8] = {0, 3, 2, 4, 1, 5, 6, 7};
    int best_baud = 0;
    int divisor, best_divisor;
    if (baudrate >=  clk/clk_div)
    {
        *encoded_divisor = 0;
        best_baud = clk/clk_div;
    }
    else if (baudrate >=  clk/(clk_div + clk_div/2))
    {
        *encoded_divisor = 1;
        best_baud = clk/(clk_div + clk_div/2);
    }
    else if (baudrate >=  clk/(2*clk_div))
    {
        *encoded_divisor = 2;
        best_baud = clk/(2*clk_div);
    }
    else
    {
        /* We divide by 16 to have 3 fractional bits and one bit for rounding */
        divisor = clk*16/clk_div / baudrate;
        if (divisor & 1) /* Decide if to round up or down*/
            best_divisor = divisor /2 +1;
        else
            best_divisor = divisor/2;
        if(best_divisor > 0x20000)
            best_divisor = 0x1ffff;
        best_baud = clk*16/clk_div/best_divisor;
        if (best_baud & 1) /* Decide if to round up or down*/
            best_baud = best_baud /2 +1;
        else
            best_baud = best_baud /2;
        *encoded_divisor = (best_divisor >> 3) | (frac_code[best_divisor & 0x7] << 14);
    }
    return best_baud;
} 
static int ftdi_convert_baudrate(int baudrate, struct ftdi_context *ftdi,
                                 unsigned short *value, unsigned short *index)
{
    int best_baud;
    unsigned long encoded_divisor;

    if (baudrate <= 0)
    {
        // Return error
        return -1;
    }

#define H_CLK 120000000
#define C_CLK  48000000
    if ((ftdi->type == TYPE_2232H) || (ftdi->type == TYPE_4232H) || (ftdi->type == TYPE_232H ))
    {
        if(baudrate*10 > H_CLK /0x3fff)
        {
            /* On H Devices, use 12 000 000 Baudrate when possible
               We have a 14 bit divisor, a 1 bit divisor switch (10 or 16) 
               three fractional bits and a 120 MHz clock
               Assume AN_120 "Sub-integer divisors between 0 and 2 are not allowed" holds for
               DIV/10 CLK too, so /1, /1.5 and /2 can be handled the same*/
            best_baud = ftdi_to_clkbits(baudrate, H_CLK, 10, &encoded_divisor);
            encoded_divisor |= 0x20000; /* switch on CLK/10*/
        }
        else
            best_baud = ftdi_to_clkbits(baudrate, C_CLK, 16, &encoded_divisor);
    }
    else if ((ftdi->type == TYPE_BM) || (ftdi->type == TYPE_2232C) || (ftdi->type == TYPE_R ))
    {
        best_baud = ftdi_to_clkbits(baudrate, C_CLK, 16, &encoded_divisor);
    }
    else
    {
        best_baud = ftdi_to_clkbits_AM(baudrate, &encoded_divisor);
    }
    // Split into "value" and "index" values
    *value = (unsigned short)(encoded_divisor & 0xFFFF);
    if (ftdi->type == TYPE_2232H || 
        ftdi->type == TYPE_4232H || ftdi->type == TYPE_232H )
    {
        *index = (unsigned short)(encoded_divisor >> 8);
        *index &= 0xFF00;
        *index |= ftdi->index;
    }
    else
        *index = (unsigned short)(encoded_divisor >> 16);

    // Return the nearest baud rate
    return best_baud;
}

int convert_baudrate_UT_export(int baudrate, struct ftdi_context *ftdi,
                                 unsigned short *value, unsigned short *index)
{
    return ftdi_convert_baudrate(baudrate, ftdi, value, index);
}

int ftdi_set_baudrate(struct ftdi_context *ftdi, int baudrate)
{
    unsigned short value, index;
    int actual_baudrate;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-3, "USB device unavailable");

    if (ftdi->bitbang_enabled)
    {
        baudrate = baudrate*4;
    }

    actual_baudrate = ftdi_convert_baudrate(baudrate, ftdi, &value, &index);
    if (actual_baudrate <= 0)
        ftdi_error_return (-1, "Silly baudrate <= 0.");

    // Check within tolerance (about 5%)
    if ((actual_baudrate * 2 < baudrate /* Catch overflows */ )
            || ((actual_baudrate < baudrate)
                ? (actual_baudrate * 21 < baudrate * 20)
                : (baudrate * 21 < actual_baudrate * 20)))
        ftdi_error_return (-1, "Unsupported baudrate. Note: bitbang baudrates are automatically multiplied by 4");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_SET_BAUDRATE_REQUEST, value,
                                index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return (-2, "Setting new baudrate failed");

    ftdi->baudrate = baudrate;
    return 0;
}

int ftdi_set_line_property(struct ftdi_context *ftdi, enum ftdi_bits_type bits,
                           enum ftdi_stopbits_type sbit, enum ftdi_parity_type parity)
{
    return ftdi_set_line_property2(ftdi, bits, sbit, parity, BREAK_OFF);
}

int ftdi_set_line_property2(struct ftdi_context *ftdi, enum ftdi_bits_type bits,
                            enum ftdi_stopbits_type sbit, enum ftdi_parity_type parity,
                            enum ftdi_break_type break_type)
{
    unsigned short value = bits;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    switch (parity)
    {
        case NONE:
            value |= (0x00 << 8);
            break;
        case ODD:
            value |= (0x01 << 8);
            break;
        case EVEN:
            value |= (0x02 << 8);
            break;
        case MARK:
            value |= (0x03 << 8);
            break;
        case SPACE:
            value |= (0x04 << 8);
            break;
    }

    switch (sbit)
    {
        case STOP_BIT_1:
            value |= (0x00 << 11);
            break;
        case STOP_BIT_15:
            value |= (0x01 << 11);
            break;
        case STOP_BIT_2:
            value |= (0x02 << 11);
            break;
    }

    switch (break_type)
    {
        case BREAK_OFF:
            value |= (0x00 << 14);
            break;
        case BREAK_ON:
            value |= (0x01 << 14);
            break;
    }

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_SET_DATA_REQUEST, value,
                                ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return (-1, "Setting new line property failed");

    return 0;
}

int ftdi_write_data(struct ftdi_context *ftdi, unsigned char *buf, int size)
{
    int offset = 0;
    int actual_length;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-666, "USB device unavailable");

    while (offset < size)
    {
        int write_size = ftdi->writebuffer_chunksize;

        if (offset+write_size > size)
            write_size = size-offset;

        if (libusb_bulk_transfer(ftdi->usb_dev, ftdi->in_ep, buf+offset, write_size, &actual_length, ftdi->usb_write_timeout) < 0)
            ftdi_error_return(-1, "usb bulk write failed");

        offset += actual_length;
    }

    return offset;
}

static void ftdi_read_data_cb(struct libusb_transfer *transfer)
{
    struct ftdi_transfer_control *tc = (struct ftdi_transfer_control *) transfer->user_data;
    struct ftdi_context *ftdi = tc->ftdi;
    int packet_size, actual_length, num_of_chunks, chunk_remains, i, ret;

    packet_size = ftdi->max_packet_size;

    actual_length = transfer->actual_length;

    if (actual_length > 2)
    {
        // skip FTDI status bytes.
        // Maybe stored in the future to enable modem use
        num_of_chunks = actual_length / packet_size;
        chunk_remains = actual_length % packet_size;
        //printf("actual_length = %X, num_of_chunks = %X, chunk_remains = %X, readbuffer_offset = %X\n", actual_length, num_of_chunks, chunk_remains, ftdi->readbuffer_offset);

        ftdi->readbuffer_offset += 2;
        actual_length -= 2;

        if (actual_length > packet_size - 2)
        {
            for (i = 1; i < num_of_chunks; i++)
                memmove (ftdi->readbuffer+ftdi->readbuffer_offset+(packet_size - 2)*i,
                         ftdi->readbuffer+ftdi->readbuffer_offset+packet_size*i,
                         packet_size - 2);
            if (chunk_remains > 2)
            {
                memmove (ftdi->readbuffer+ftdi->readbuffer_offset+(packet_size - 2)*i,
                         ftdi->readbuffer+ftdi->readbuffer_offset+packet_size*i,
                         chunk_remains-2);
                actual_length -= 2*num_of_chunks;
            }
            else
                actual_length -= 2*(num_of_chunks-1)+chunk_remains;
        }

        if (actual_length > 0)
        {
            // data still fits in buf?
            if (tc->offset + actual_length <= tc->size)
            {
                memcpy (tc->buf + tc->offset, ftdi->readbuffer + ftdi->readbuffer_offset, actual_length);
                //printf("buf[0] = %X, buf[1] = %X\n", buf[0], buf[1]);
                tc->offset += actual_length;

                ftdi->readbuffer_offset = 0;
                ftdi->readbuffer_remaining = 0;

                /* Did we read exactly the right amount of bytes? */
                if (tc->offset == tc->size)
                {
                    //printf("read_data exact rem %d offset %d\n",
                    //ftdi->readbuffer_remaining, offset);
                    tc->completed = 1;
                    return;
                }
            }
            else
            {
                // only copy part of the data or size <= readbuffer_chunksize
                int part_size = tc->size - tc->offset;
                memcpy (tc->buf + tc->offset, ftdi->readbuffer + ftdi->readbuffer_offset, part_size);
                tc->offset += part_size;

                ftdi->readbuffer_offset += part_size;
                ftdi->readbuffer_remaining = actual_length - part_size;

                /* printf("Returning part: %d - size: %d - offset: %d - actual_length: %d - remaining: %d\n",
                part_size, size, offset, actual_length, ftdi->readbuffer_remaining); */
                tc->completed = 1;
                return;
            }
        }
    }
    ret = libusb_submit_transfer (transfer);
    if (ret < 0)
        tc->completed = 1;
}


static void ftdi_write_data_cb(struct libusb_transfer *transfer)
{
    struct ftdi_transfer_control *tc = (struct ftdi_transfer_control *) transfer->user_data;
    struct ftdi_context *ftdi = tc->ftdi;

    tc->offset += transfer->actual_length;

    if (tc->offset == tc->size)
    {
        tc->completed = 1;
    }
    else
    {
        int write_size = ftdi->writebuffer_chunksize;
        int ret;

        if (tc->offset + write_size > tc->size)
            write_size = tc->size - tc->offset;

        transfer->length = write_size;
        transfer->buffer = tc->buf + tc->offset;
        ret = libusb_submit_transfer (transfer);
        if (ret < 0)
            tc->completed = 1;
    }
}


struct ftdi_transfer_control *ftdi_write_data_submit(struct ftdi_context *ftdi, unsigned char *buf, int size)
{
    struct ftdi_transfer_control *tc;
    struct libusb_transfer *transfer;
    int write_size, ret;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        return NULL;

    tc = (struct ftdi_transfer_control *) malloc (sizeof (*tc));
    if (!tc)
        return NULL;

    transfer = libusb_alloc_transfer(0);
    if (!transfer)
    {
        free(tc);
        return NULL;
    }

    tc->ftdi = ftdi;
    tc->completed = 0;
    tc->buf = buf;
    tc->size = size;
    tc->offset = 0;

    if (size < ftdi->writebuffer_chunksize)
        write_size = size;
    else
        write_size = ftdi->writebuffer_chunksize;

    libusb_fill_bulk_transfer(transfer, ftdi->usb_dev, ftdi->in_ep, buf,
                              write_size, ftdi_write_data_cb, tc,
                              ftdi->usb_write_timeout);
    transfer->type = LIBUSB_TRANSFER_TYPE_BULK;

    ret = libusb_submit_transfer(transfer);
    if (ret < 0)
    {
        libusb_free_transfer(transfer);
        free(tc);
        return NULL;
    }
    tc->transfer = transfer;

    return tc;
}

struct ftdi_transfer_control *ftdi_read_data_submit(struct ftdi_context *ftdi, unsigned char *buf, int size)
{
    struct ftdi_transfer_control *tc;
    struct libusb_transfer *transfer;
    int ret;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        return NULL;

    tc = (struct ftdi_transfer_control *) malloc (sizeof (*tc));
    if (!tc)
        return NULL;

    tc->ftdi = ftdi;
    tc->buf = buf;
    tc->size = size;

    if (size <= ftdi->readbuffer_remaining)
    {
        memcpy (buf, ftdi->readbuffer+ftdi->readbuffer_offset, size);

        // Fix offsets
        ftdi->readbuffer_remaining -= size;
        ftdi->readbuffer_offset += size;

        /* printf("Returning bytes from buffer: %d - remaining: %d\n", size, ftdi->readbuffer_remaining); */

        tc->completed = 1;
        tc->offset = size;
        tc->transfer = NULL;
        return tc;
    }

    tc->completed = 0;
    if (ftdi->readbuffer_remaining != 0)
    {
        memcpy (buf, ftdi->readbuffer+ftdi->readbuffer_offset, ftdi->readbuffer_remaining);

        tc->offset = ftdi->readbuffer_remaining;
    }
    else
        tc->offset = 0;

    transfer = libusb_alloc_transfer(0);
    if (!transfer)
    {
        free (tc);
        return NULL;
    }

    ftdi->readbuffer_remaining = 0;
    ftdi->readbuffer_offset = 0;

    libusb_fill_bulk_transfer(transfer, ftdi->usb_dev, ftdi->out_ep, ftdi->readbuffer, ftdi->readbuffer_chunksize, ftdi_read_data_cb, tc, ftdi->usb_read_timeout);
    transfer->type = LIBUSB_TRANSFER_TYPE_BULK;

    ret = libusb_submit_transfer(transfer);
    if (ret < 0)
    {
        libusb_free_transfer(transfer);
        free (tc);
        return NULL;
    }
    tc->transfer = transfer;

    return tc;
}

int ftdi_transfer_data_done(struct ftdi_transfer_control *tc)
{
    int ret;

    while (!tc->completed)
    {
        ret = libusb_handle_events(tc->ftdi->usb_ctx);
        if (ret < 0)
        {
            if (ret == LIBUSB_ERROR_INTERRUPTED)
                continue;
            libusb_cancel_transfer(tc->transfer);
            while (!tc->completed)
                if (libusb_handle_events(tc->ftdi->usb_ctx) < 0)
                    break;
            libusb_free_transfer(tc->transfer);
            free (tc);
            return ret;
        }
    }

    ret = tc->offset;
    if (tc->transfer)
    {
        if (tc->transfer->status != LIBUSB_TRANSFER_COMPLETED)
            ret = -1;
        libusb_free_transfer(tc->transfer);
    }
    free(tc);
    return ret;
}

int ftdi_write_data_set_chunksize(struct ftdi_context *ftdi, unsigned int chunksize)
{
    if (ftdi == NULL)
        ftdi_error_return(-1, "ftdi context invalid");

    ftdi->writebuffer_chunksize = chunksize;
    return 0;
}

int ftdi_write_data_get_chunksize(struct ftdi_context *ftdi, unsigned int *chunksize)
{
    if (ftdi == NULL)
        ftdi_error_return(-1, "ftdi context invalid");

    *chunksize = ftdi->writebuffer_chunksize;
    return 0;
}

int ftdi_read_data(struct ftdi_context *ftdi, unsigned char *buf, int size)
{
    int offset = 0, ret, i, num_of_chunks, chunk_remains;
    int packet_size = ftdi->max_packet_size;
    int actual_length = 1;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-666, "USB device unavailable");

    // Packet size sanity check (avoid division by zero)
    if (packet_size == 0)
        ftdi_error_return(-1, "max_packet_size is bogus (zero)");

    // everything we want is still in the readbuffer?
    if (size <= ftdi->readbuffer_remaining)
    {
        memcpy (buf, ftdi->readbuffer+ftdi->readbuffer_offset, size);

        // Fix offsets
        ftdi->readbuffer_remaining -= size;
        ftdi->readbuffer_offset += size;

        /* printf("Returning bytes from buffer: %d - remaining: %d\n", size, ftdi->readbuffer_remaining); */

        return size;
    }
    // something still in the readbuffer, but not enough to satisfy 'size'?
    if (ftdi->readbuffer_remaining != 0)
    {
        memcpy (buf, ftdi->readbuffer+ftdi->readbuffer_offset, ftdi->readbuffer_remaining);

        // Fix offset
        offset += ftdi->readbuffer_remaining;
    }
    // do the actual USB read
    while (offset < size && actual_length > 0)
    {
        ftdi->readbuffer_remaining = 0;
        ftdi->readbuffer_offset = 0;
        /* returns how much received */
        ret = libusb_bulk_transfer (ftdi->usb_dev, ftdi->out_ep, ftdi->readbuffer, ftdi->readbuffer_chunksize, &actual_length, ftdi->usb_read_timeout);
        if (ret < 0)
            ftdi_error_return(ret, "usb bulk read failed");

        if (actual_length > 2)
        {
            // skip FTDI status bytes.
            // Maybe stored in the future to enable modem use
            num_of_chunks = actual_length / packet_size;
            chunk_remains = actual_length % packet_size;
            //printf("actual_length = %X, num_of_chunks = %X, chunk_remains = %X, readbuffer_offset = %X\n", actual_length, num_of_chunks, chunk_remains, ftdi->readbuffer_offset);

            ftdi->readbuffer_offset += 2;
            actual_length -= 2;

            if (actual_length > packet_size - 2)
            {
                for (i = 1; i < num_of_chunks; i++)
                    memmove (ftdi->readbuffer+ftdi->readbuffer_offset+(packet_size - 2)*i,
                             ftdi->readbuffer+ftdi->readbuffer_offset+packet_size*i,
                             packet_size - 2);
                if (chunk_remains > 2)
                {
                    memmove (ftdi->readbuffer+ftdi->readbuffer_offset+(packet_size - 2)*i,
                             ftdi->readbuffer+ftdi->readbuffer_offset+packet_size*i,
                             chunk_remains-2);
                    actual_length -= 2*num_of_chunks;
                }
                else
                    actual_length -= 2*(num_of_chunks-1)+chunk_remains;
            }
        }
        else if (actual_length <= 2)
        {
            // no more data to read?
            return offset;
        }
        if (actual_length > 0)
        {
            // data still fits in buf?
            if (offset+actual_length <= size)
            {
                memcpy (buf+offset, ftdi->readbuffer+ftdi->readbuffer_offset, actual_length);
                //printf("buf[0] = %X, buf[1] = %X\n", buf[0], buf[1]);
                offset += actual_length;

                /* Did we read exactly the right amount of bytes? */
                if (offset == size)
                    //printf("read_data exact rem %d offset %d\n",
                    //ftdi->readbuffer_remaining, offset);
                    return offset;
            }
            else
            {
                // only copy part of the data or size <= readbuffer_chunksize
                int part_size = size-offset;
                memcpy (buf+offset, ftdi->readbuffer+ftdi->readbuffer_offset, part_size);

                ftdi->readbuffer_offset += part_size;
                ftdi->readbuffer_remaining = actual_length-part_size;
                offset += part_size;

                /* printf("Returning part: %d - size: %d - offset: %d - actual_length: %d - remaining: %d\n",
                part_size, size, offset, actual_length, ftdi->readbuffer_remaining); */

                return offset;
            }
        }
    }
    // never reached
    return -127;
}

int ftdi_read_data_set_chunksize(struct ftdi_context *ftdi, unsigned int chunksize)
{
    unsigned char *new_buf;

    if (ftdi == NULL)
        ftdi_error_return(-1, "ftdi context invalid");

    // Invalidate all remaining data
    ftdi->readbuffer_offset = 0;
    ftdi->readbuffer_remaining = 0;
#ifdef __linux__
    /* We can't set readbuffer_chunksize larger than MAX_BULK_BUFFER_LENGTH,
       which is defined in libusb-1.0.  Otherwise, each USB read request will
       be divided into multiple URBs.  This will cause issues on Linux kernel
       older than 2.6.32.  */
    if (chunksize > 16384)
        chunksize = 16384;
#endif

    if ((new_buf = (unsigned char *)realloc(ftdi->readbuffer, chunksize)) == NULL)
        ftdi_error_return(-1, "out of memory for readbuffer");

    ftdi->readbuffer = new_buf;
    ftdi->readbuffer_chunksize = chunksize;

    return 0;
}

int ftdi_read_data_get_chunksize(struct ftdi_context *ftdi, unsigned int *chunksize)
{
    if (ftdi == NULL)
        ftdi_error_return(-1, "FTDI context invalid");

    *chunksize = ftdi->readbuffer_chunksize;
    return 0;
}

int ftdi_set_bitmode(struct ftdi_context *ftdi, unsigned char bitmask, unsigned char mode)
{
    unsigned short usb_val;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    usb_val = bitmask; // low byte: bitmask
    usb_val |= (mode << 8);
    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_BITMODE_REQUEST, usb_val, ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "unable to configure bitbang mode. Perhaps not a BM/2232C type chip?");

    ftdi->bitbang_mode = mode;
    ftdi->bitbang_enabled = (mode == BITMODE_RESET) ? 0 : 1;
    return 0;
}

int ftdi_disable_bitbang(struct ftdi_context *ftdi)
{
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_BITMODE_REQUEST, 0, ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "unable to leave bitbang mode. Perhaps not a BM type chip?");

    ftdi->bitbang_enabled = 0;
    return 0;
}


int ftdi_read_pins(struct ftdi_context *ftdi, unsigned char *pins)
{
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_PINS_REQUEST, 0, ftdi->index, (unsigned char *)pins, 1, ftdi->usb_read_timeout) != 1)
        ftdi_error_return(-1, "read pins failed");

    return 0;
}

int ftdi_set_latency_timer(struct ftdi_context *ftdi, unsigned char latency)
{
    unsigned short usb_val;

    if (latency < 1)
        ftdi_error_return(-1, "latency out of range. Only valid for 1-255");

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-3, "USB device unavailable");

    usb_val = latency;
    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_LATENCY_TIMER_REQUEST, usb_val, ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-2, "unable to set latency timer");

    return 0;
}

int ftdi_get_latency_timer(struct ftdi_context *ftdi, unsigned char *latency)
{
    unsigned short usb_val;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_GET_LATENCY_TIMER_REQUEST, 0, ftdi->index, (unsigned char *)&usb_val, 1, ftdi->usb_read_timeout) != 1)
        ftdi_error_return(-1, "reading latency timer failed");

    *latency = (unsigned char)usb_val;
    return 0;
}

int ftdi_poll_modem_status(struct ftdi_context *ftdi, unsigned short *status)
{
    char usb_val[2];

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_POLL_MODEM_STATUS_REQUEST, 0, ftdi->index, (unsigned char *)usb_val, 2, ftdi->usb_read_timeout) != 2)
        ftdi_error_return(-1, "getting modem status failed");

    *status = (usb_val[1] << 8) | (usb_val[0] & 0xFF);

    return 0;
}

int ftdi_setflowctrl(struct ftdi_context *ftdi, int flowctrl)
{
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_SET_FLOW_CTRL_REQUEST, 0, (flowctrl | ftdi->index),
                                NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "set flow control failed");

    return 0;
}

int ftdi_setdtr(struct ftdi_context *ftdi, int state)
{
    unsigned short usb_val;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (state)
        usb_val = SIO_SET_DTR_HIGH;
    else
        usb_val = SIO_SET_DTR_LOW;

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_SET_MODEM_CTRL_REQUEST, usb_val, ftdi->index,
                                NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "set dtr failed");

    return 0;
}

int ftdi_setrts(struct ftdi_context *ftdi, int state)
{
    unsigned short usb_val;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (state)
        usb_val = SIO_SET_RTS_HIGH;
    else
        usb_val = SIO_SET_RTS_LOW;

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_SET_MODEM_CTRL_REQUEST, usb_val, ftdi->index,
                                NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "set of rts failed");

    return 0;
}

int ftdi_setdtr_rts(struct ftdi_context *ftdi, int dtr, int rts)
{
    unsigned short usb_val;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (dtr)
        usb_val = SIO_SET_DTR_HIGH;
    else
        usb_val = SIO_SET_DTR_LOW;

    if (rts)
        usb_val |= SIO_SET_RTS_HIGH;
    else
        usb_val |= SIO_SET_RTS_LOW;

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_SET_MODEM_CTRL_REQUEST, usb_val, ftdi->index,
                                NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "set of rts/dtr failed");

    return 0;
}

int ftdi_set_event_char(struct ftdi_context *ftdi,
                        unsigned char eventch, unsigned char enable)
{
    unsigned short usb_val;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    usb_val = eventch;
    if (enable)
        usb_val |= 1 << 8;

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_EVENT_CHAR_REQUEST, usb_val, ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "setting event character failed");

    return 0;
}

int ftdi_set_error_char(struct ftdi_context *ftdi,
                        unsigned char errorch, unsigned char enable)
{
    unsigned short usb_val;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    usb_val = errorch;
    if (enable)
        usb_val |= 1 << 8;

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_SET_ERROR_CHAR_REQUEST, usb_val, ftdi->index, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "setting error character failed");

    return 0;
}

int ftdi_eeprom_initdefaults(struct ftdi_context *ftdi, char * manufacturer,
                             char * product, char * serial)
{
    struct ftdi_eeprom *eeprom;

    if (ftdi == NULL)
        ftdi_error_return(-1, "No struct ftdi_context");

    if (ftdi->eeprom == NULL)
        ftdi_error_return(-2,"No struct ftdi_eeprom");

    eeprom = ftdi->eeprom;
    memset(eeprom, 0, sizeof(struct ftdi_eeprom));

    if (ftdi->usb_dev == NULL)
        ftdi_error_return(-3, "No connected device or device not yet opened");

    eeprom->vendor_id = 0x0403;
    eeprom->use_serial = 1;
    if ((ftdi->type == TYPE_AM) || (ftdi->type == TYPE_BM) ||
            (ftdi->type == TYPE_R))
        eeprom->product_id = 0x6001;
    else if (ftdi->type == TYPE_4232H)
        eeprom->product_id = 0x6011;
    else if (ftdi->type == TYPE_232H)
        eeprom->product_id = 0x6014;
    else
        eeprom->product_id = 0x6010;
    if (ftdi->type == TYPE_AM)
        eeprom->usb_version = 0x0101;
    else
        eeprom->usb_version = 0x0200;
    eeprom->max_power = 100;

    if (eeprom->manufacturer)
        free (eeprom->manufacturer);
    eeprom->manufacturer = NULL;
    if (manufacturer)
    {
        eeprom->manufacturer = malloc(strlen(manufacturer)+1);
        if (eeprom->manufacturer)
            strcpy(eeprom->manufacturer, manufacturer);
    }

    if (eeprom->product)
        free (eeprom->product);
    eeprom->product = NULL;
    if(product)
    {
        eeprom->product = malloc(strlen(product)+1);
        if (eeprom->product)
            strcpy(eeprom->product, product);
    }
    else
    {
        const char* default_product;
        switch(ftdi->type)
        {
        case TYPE_AM:    default_product = "AM"; break;
        case TYPE_BM:    default_product = "BM"; break;
        case TYPE_2232C: default_product = "Dual RS232"; break;
        case TYPE_R:     default_product = "FT232R USB UART"; break;
        case TYPE_2232H: default_product = "Dual RS232-HS"; break;
        case TYPE_4232H: default_product = "FT4232H"; break;
        case TYPE_232H:  default_product = "Single-RS232-HS"; break;
        default:
        ftdi_error_return(-3, "Unknown chip type");
        }
        eeprom->product = malloc(strlen(default_product) +1);
        if (eeprom->product)
            strcpy(eeprom->product, default_product);
    }

    if (eeprom->serial)
        free (eeprom->serial);
    eeprom->serial = NULL;
    if (serial)
    {
        eeprom->serial = malloc(strlen(serial)+1);
        if (eeprom->serial)
            strcpy(eeprom->serial, serial);
    }

    if (ftdi->type == TYPE_R)
    {
        eeprom->max_power = 90;
        eeprom->size = 0x80;
        eeprom->cbus_function[0] = CBUS_TXLED;
        eeprom->cbus_function[1] = CBUS_RXLED;
        eeprom->cbus_function[2] = CBUS_TXDEN;
        eeprom->cbus_function[3] = CBUS_PWREN;
        eeprom->cbus_function[4] = CBUS_SLEEP;
    }
    else
    {
        if(ftdi->type == TYPE_232H)
        {
            int i;
            for (i=0; i<10; i++)
                eeprom->cbus_function[i] = CBUSH_TRISTATE;
        }
        eeprom->size = -1;
    }
    eeprom->initialized_for_connected_device = 1;
    return 0;
}
/*FTD2XX doesn't check for values not fitting in the ACBUS Signal oprtions*/
void set_ft232h_cbus(struct ftdi_eeprom *eeprom, unsigned char * output)
{
    int i;
    for(i=0; i<5;i++)
    {
        int mode_low, mode_high;
        if (eeprom->cbus_function[2*i]> CBUSH_CLK7_5)
            mode_low = CBUSH_TRISTATE;
        else
            mode_low = eeprom->cbus_function[2*i];
        if (eeprom->cbus_function[2*i+1]> CBUSH_CLK7_5)
            mode_high = CBUSH_TRISTATE;
        else
            mode_high = eeprom->cbus_function[2*i+1];

        output[0x18+i] = (mode_high <<4) | mode_low;
    }
}
/* Return the bits for the encoded EEPROM Structure of a requested Mode
 *
 */
static unsigned char type2bit(unsigned char type, enum ftdi_chip_type chip)
{
    switch (chip)
    {
    case TYPE_2232H:
    case TYPE_2232C:
    {
        switch (type)
        {
        case CHANNEL_IS_UART: return 0;
        case CHANNEL_IS_FIFO: return 0x01;
        case CHANNEL_IS_OPTO: return 0x02;
        case CHANNEL_IS_CPU : return 0x04;
        default: return 0;
        }
    }
    case TYPE_232H:
    {
        switch (type)
        {
        case CHANNEL_IS_UART   : return 0;
        case CHANNEL_IS_FIFO   : return 0x01;
        case CHANNEL_IS_OPTO   : return 0x02;
        case CHANNEL_IS_CPU    : return 0x04;
        case CHANNEL_IS_FT1284 : return 0x08;
        default: return 0;
        }
    }
    default: return 0;
    }
    return 0;
}    

int ftdi_eeprom_build(struct ftdi_context *ftdi)
{
    unsigned char i, j, eeprom_size_mask;
    unsigned short checksum, value;
    unsigned char manufacturer_size = 0, product_size = 0, serial_size = 0;
    int user_area_size;
    struct ftdi_eeprom *eeprom;
    unsigned char * output;

    if (ftdi == NULL)
        ftdi_error_return(-2,"No context");
    if (ftdi->eeprom == NULL)
        ftdi_error_return(-2,"No eeprom structure");

    eeprom= ftdi->eeprom;
    output = eeprom->buf;

    if (eeprom->chip == -1)
        ftdi_error_return(-6,"No connected EEPROM or EEPROM type unknown");

    if ((eeprom->chip == 0x56) || (eeprom->chip == 0x66))
        eeprom->size = 0x100;
    else
        eeprom->size = 0x80;

    if (eeprom->manufacturer != NULL)
        manufacturer_size = strlen(eeprom->manufacturer);
    if (eeprom->product != NULL)
        product_size = strlen(eeprom->product);
    if (eeprom->serial != NULL)
        serial_size = strlen(eeprom->serial);

    // eeprom size check
    switch (ftdi->type)
    {
        case TYPE_AM:
        case TYPE_BM:
            user_area_size = 96;    // base size for strings (total of 48 characters)
            break;
        case TYPE_2232C:
            user_area_size = 90;     // two extra config bytes and 4 bytes PnP stuff
            break;
        case TYPE_R:
            user_area_size = 88;     // four extra config bytes + 4 bytes PnP stuff
            break;
        case TYPE_2232H:            // six extra config bytes + 4 bytes PnP stuff
        case TYPE_4232H:
            user_area_size = 86;
            break;
        case TYPE_232H:
            user_area_size = 80;
            break;
        default:
            user_area_size = 0;
            break;
    }
    user_area_size  -= (manufacturer_size + product_size + serial_size) * 2;

    if (user_area_size < 0)
        ftdi_error_return(-1,"eeprom size exceeded");

    // empty eeprom
    memset (ftdi->eeprom->buf, 0, FTDI_MAX_EEPROM_SIZE);

    // Bytes and Bits set for all Types

    // Addr 02: Vendor ID
    output[0x02] = eeprom->vendor_id;
    output[0x03] = eeprom->vendor_id >> 8;

    // Addr 04: Product ID
    output[0x04] = eeprom->product_id;
    output[0x05] = eeprom->product_id >> 8;

    // Addr 06: Device release number (0400h for BM features)
    output[0x06] = 0x00;
    switch (ftdi->type)
    {
        case TYPE_AM:
            output[0x07] = 0x02;
            break;
        case TYPE_BM:
            output[0x07] = 0x04;
            break;
        case TYPE_2232C:
            output[0x07] = 0x05;
            break;
        case TYPE_R:
            output[0x07] = 0x06;
            break;
        case TYPE_2232H:
            output[0x07] = 0x07;
            break;
        case TYPE_4232H:
            output[0x07] = 0x08;
            break;
        case TYPE_232H:
            output[0x07] = 0x09;
            break;
        default:
            output[0x07] = 0x00;
    }

    // Addr 08: Config descriptor
    // Bit 7: always 1
    // Bit 6: 1 if this device is self powered, 0 if bus powered
    // Bit 5: 1 if this device uses remote wakeup
    // Bit 4-0: reserved - 0
    j = 0x80;
    if (eeprom->self_powered == 1)
        j |= 0x40;
    if (eeprom->remote_wakeup == 1)
        j |= 0x20;
    output[0x08] = j;

    // Addr 09: Max power consumption: max power = value * 2 mA
    output[0x09] = eeprom->max_power / MAX_POWER_MILLIAMP_PER_UNIT;

    if (ftdi->type != TYPE_AM)
    {
        // Addr 0A: Chip configuration
        // Bit 7: 0 - reserved
        // Bit 6: 0 - reserved
        // Bit 5: 0 - reserved
        // Bit 4: 1 - Change USB version
        // Bit 3: 1 - Use the serial number string
        // Bit 2: 1 - Enable suspend pull downs for lower power
        // Bit 1: 1 - Out EndPoint is Isochronous
        // Bit 0: 1 - In EndPoint is Isochronous
        //
        j = 0;
        if (eeprom->in_is_isochronous == 1)
            j = j | 1;
        if (eeprom->out_is_isochronous == 1)
            j = j | 2;
        output[0x0A] = j;
    }

    // Dynamic content
    // Strings start at 0x94 (TYPE_AM, TYPE_BM)
    // 0x96 (TYPE_2232C), 0x98 (TYPE_R) and 0x9a (TYPE_x232H)
    // 0xa0 (TYPE_232H)
    i = 0;
    switch (ftdi->type)
    {
        case TYPE_232H:
            i += 2;
        case TYPE_2232H:
        case TYPE_4232H:
            i += 2;
        case TYPE_R:
            i += 2;
        case TYPE_2232C:
            i += 2;
        case TYPE_AM:
        case TYPE_BM:
            i += 0x94;
    }
    /* Wrap around 0x80 for 128 byte EEPROMS (Internale and 93x46) */
    eeprom_size_mask = eeprom->size -1;

    // Addr 0E: Offset of the manufacturer string + 0x80, calculated later
    // Addr 0F: Length of manufacturer string
    // Output manufacturer
    output[0x0E] = i;  // calculate offset
    output[i & eeprom_size_mask] = manufacturer_size*2 + 2, i++;
    output[i & eeprom_size_mask] = 0x03, i++; // type: string
    for (j = 0; j < manufacturer_size; j++)
    {
        output[i & eeprom_size_mask] = eeprom->manufacturer[j], i++;
        output[i & eeprom_size_mask] = 0x00, i++;
    }
    output[0x0F] = manufacturer_size*2 + 2;

    // Addr 10: Offset of the product string + 0x80, calculated later
    // Addr 11: Length of product string
    output[0x10] = i | 0x80;  // calculate offset
    output[i & eeprom_size_mask] = product_size*2 + 2, i++;
    output[i & eeprom_size_mask] = 0x03, i++;
    for (j = 0; j < product_size; j++)
    {
        output[i & eeprom_size_mask] = eeprom->product[j], i++;
        output[i & eeprom_size_mask] = 0x00, i++;
    }
    output[0x11] = product_size*2 + 2;

    // Addr 12: Offset of the serial string + 0x80, calculated later
    // Addr 13: Length of serial string
    output[0x12] = i | 0x80; // calculate offset
    output[i & eeprom_size_mask] = serial_size*2 + 2, i++;
    output[i & eeprom_size_mask] = 0x03, i++;
    for (j = 0; j < serial_size; j++)
    {
        output[i & eeprom_size_mask] = eeprom->serial[j], i++;
        output[i & eeprom_size_mask] = 0x00, i++;
    }

    // Legacy port name and PnP fields for FT2232 and newer chips
    if (ftdi->type > TYPE_BM)
    {
        output[i & eeprom_size_mask] = 0x02; /* as seen when written with FTD2XX */
        i++;
        output[i & eeprom_size_mask] = 0x03; /* as seen when written with FTD2XX */
        i++;
        output[i & eeprom_size_mask] = eeprom->is_not_pnp; /* as seen when written with FTD2XX */
        i++;
    }

    output[0x13] = serial_size*2 + 2;

    if (ftdi->type > TYPE_AM) /* use_serial not used in AM devices */
    {
        if (eeprom->use_serial)
            output[0x0A] |= USE_SERIAL_NUM;
        else
            output[0x0A] &= ~USE_SERIAL_NUM;
    }

    /* Bytes and Bits specific to (some) types
       Write linear, as this allows easier fixing*/
    switch (ftdi->type)
    {
        case TYPE_AM:
            break;
        case TYPE_BM:
            output[0x0C] = eeprom->usb_version & 0xff;
            output[0x0D] = (eeprom->usb_version>>8) & 0xff;
            if (eeprom->use_usb_version == USE_USB_VERSION_BIT)
                output[0x0A] |= USE_USB_VERSION_BIT;
            else
                output[0x0A] &= ~USE_USB_VERSION_BIT;

            break;
        case TYPE_2232C:

            output[0x00] = type2bit(eeprom->channel_a_type, TYPE_2232C);
            if ( eeprom->channel_a_driver == DRIVER_VCP)
                output[0x00] |= DRIVER_VCP;
            else
                output[0x00] &= ~DRIVER_VCP;

            if ( eeprom->high_current_a == HIGH_CURRENT_DRIVE)
                output[0x00] |= HIGH_CURRENT_DRIVE;
            else
                output[0x00] &= ~HIGH_CURRENT_DRIVE;

            output[0x01] = type2bit(eeprom->channel_b_type, TYPE_2232C);
            if ( eeprom->channel_b_driver == DRIVER_VCP)
                output[0x01] |= DRIVER_VCP;
            else
                output[0x01] &= ~DRIVER_VCP;

            if ( eeprom->high_current_b == HIGH_CURRENT_DRIVE)
                output[0x01] |= HIGH_CURRENT_DRIVE;
            else
                output[0x01] &= ~HIGH_CURRENT_DRIVE;

            if (eeprom->in_is_isochronous == 1)
                output[0x0A] |= 0x1;
            else
                output[0x0A] &= ~0x1;
            if (eeprom->out_is_isochronous == 1)
                output[0x0A] |= 0x2;
            else
                output[0x0A] &= ~0x2;
            if (eeprom->suspend_pull_downs == 1)
                output[0x0A] |= 0x4;
            else
                output[0x0A] &= ~0x4;
            if (eeprom->use_usb_version == USE_USB_VERSION_BIT)
                output[0x0A] |= USE_USB_VERSION_BIT;
            else
                output[0x0A] &= ~USE_USB_VERSION_BIT;

            output[0x0C] = eeprom->usb_version & 0xff;
            output[0x0D] = (eeprom->usb_version>>8) & 0xff;
            output[0x14] = eeprom->chip;
            break;
        case TYPE_R:
            if (eeprom->high_current == HIGH_CURRENT_DRIVE_R)
                output[0x00] |= HIGH_CURRENT_DRIVE_R;
            output[0x01] = 0x40; /* Hard coded Endpoint Size*/

            if (eeprom->suspend_pull_downs == 1)
                output[0x0A] |= 0x4;
            else
                output[0x0A] &= ~0x4;
            output[0x0B] = eeprom->invert;
            output[0x0C] = eeprom->usb_version & 0xff;
            output[0x0D] = (eeprom->usb_version>>8) & 0xff;

            if (eeprom->cbus_function[0] > CBUS_BB)
                output[0x14] = CBUS_TXLED;
            else
                output[0x14] = eeprom->cbus_function[0];

            if (eeprom->cbus_function[1] > CBUS_BB)
                output[0x14] |= CBUS_RXLED<<4;
            else
                output[0x14] |= eeprom->cbus_function[1]<<4;

            if (eeprom->cbus_function[2] > CBUS_BB)
                output[0x15] = CBUS_TXDEN;
            else
                output[0x15] = eeprom->cbus_function[2];

            if (eeprom->cbus_function[3] > CBUS_BB)
                output[0x15] |= CBUS_PWREN<<4;
            else
                output[0x15] |= eeprom->cbus_function[3]<<4;

            if (eeprom->cbus_function[4] > CBUS_CLK6)
                output[0x16] = CBUS_SLEEP;
            else
                output[0x16] = eeprom->cbus_function[4];
            break;
        case TYPE_2232H:
            output[0x00] = type2bit(eeprom->channel_a_type, TYPE_2232H);
            if ( eeprom->channel_a_driver == DRIVER_VCP)
                output[0x00] |= DRIVER_VCP;
            else
                output[0x00] &= ~DRIVER_VCP;

            output[0x01] = type2bit(eeprom->channel_b_type, TYPE_2232H);
            if ( eeprom->channel_b_driver == DRIVER_VCP)
                output[0x01] |= DRIVER_VCP;
            else
                output[0x01] &= ~DRIVER_VCP;
            if (eeprom->suspend_dbus7 == SUSPEND_DBUS7_BIT)
                output[0x01] |= SUSPEND_DBUS7_BIT;
            else
                output[0x01] &= ~SUSPEND_DBUS7_BIT;

            if (eeprom->suspend_pull_downs == 1)
                output[0x0A] |= 0x4;
            else
                output[0x0A] &= ~0x4;

            if (eeprom->group0_drive > DRIVE_16MA)
                output[0x0c] |= DRIVE_16MA;
            else
                output[0x0c] |= eeprom->group0_drive;
            if (eeprom->group0_schmitt == IS_SCHMITT)
                output[0x0c] |= IS_SCHMITT;
            if (eeprom->group0_slew == SLOW_SLEW)
                output[0x0c] |= SLOW_SLEW;

            if (eeprom->group1_drive > DRIVE_16MA)
                output[0x0c] |= DRIVE_16MA<<4;
            else
                output[0x0c] |= eeprom->group1_drive<<4;
            if (eeprom->group1_schmitt == IS_SCHMITT)
                output[0x0c] |= IS_SCHMITT<<4;
            if (eeprom->group1_slew == SLOW_SLEW)
                output[0x0c] |= SLOW_SLEW<<4;

            if (eeprom->group2_drive > DRIVE_16MA)
                output[0x0d] |= DRIVE_16MA;
            else
                output[0x0d] |= eeprom->group2_drive;
            if (eeprom->group2_schmitt == IS_SCHMITT)
                output[0x0d] |= IS_SCHMITT;
            if (eeprom->group2_slew == SLOW_SLEW)
                output[0x0d] |= SLOW_SLEW;

            if (eeprom->group3_drive > DRIVE_16MA)
                output[0x0d] |= DRIVE_16MA<<4;
            else
                output[0x0d] |= eeprom->group3_drive<<4;
            if (eeprom->group3_schmitt == IS_SCHMITT)
                output[0x0d] |= IS_SCHMITT<<4;
            if (eeprom->group3_slew == SLOW_SLEW)
                output[0x0d] |= SLOW_SLEW<<4;

            output[0x18] = eeprom->chip;

            break;
        case TYPE_4232H:
            if (eeprom->channel_a_driver == DRIVER_VCP)
                output[0x00] |= DRIVER_VCP;
            else
                output[0x00] &= ~DRIVER_VCP;
            if (eeprom->channel_b_driver == DRIVER_VCP)
                output[0x01] |= DRIVER_VCP;
            else
                output[0x01] &= ~DRIVER_VCP;
            if (eeprom->channel_c_driver == DRIVER_VCP)
                output[0x00] |= (DRIVER_VCP << 4);
            else
                output[0x00] &= ~(DRIVER_VCP << 4);
            if (eeprom->channel_d_driver == DRIVER_VCP)
                output[0x01] |= (DRIVER_VCP << 4);
            else
                output[0x01] &= ~(DRIVER_VCP << 4);

            if (eeprom->suspend_pull_downs == 1)
                output[0x0a] |= 0x4;
            else
                output[0x0a] &= ~0x4;

            if (eeprom->channel_a_rs485enable)
                output[0x0b] |= CHANNEL_IS_RS485 << 0;
            else
                output[0x0b] &= ~(CHANNEL_IS_RS485 << 0);
            if (eeprom->channel_b_rs485enable)
                output[0x0b] |= CHANNEL_IS_RS485 << 1;
            else
                output[0x0b] &= ~(CHANNEL_IS_RS485 << 1);
            if (eeprom->channel_c_rs485enable)
                output[0x0b] |= CHANNEL_IS_RS485 << 2;
            else
                output[0x0b] &= ~(CHANNEL_IS_RS485 << 2);
            if (eeprom->channel_d_rs485enable)
                output[0x0b] |= CHANNEL_IS_RS485 << 3;
            else
                output[0x0b] &= ~(CHANNEL_IS_RS485 << 3);

            if (eeprom->group0_drive > DRIVE_16MA)
                output[0x0c] |= DRIVE_16MA;
            else
                output[0x0c] |= eeprom->group0_drive;
            if (eeprom->group0_schmitt == IS_SCHMITT)
                output[0x0c] |= IS_SCHMITT;
            if (eeprom->group0_slew == SLOW_SLEW)
                output[0x0c] |= SLOW_SLEW;

            if (eeprom->group1_drive > DRIVE_16MA)
                output[0x0c] |= DRIVE_16MA<<4;
            else
                output[0x0c] |= eeprom->group1_drive<<4;
            if (eeprom->group1_schmitt == IS_SCHMITT)
                output[0x0c] |= IS_SCHMITT<<4;
            if (eeprom->group1_slew == SLOW_SLEW)
                output[0x0c] |= SLOW_SLEW<<4;

            if (eeprom->group2_drive > DRIVE_16MA)
                output[0x0d] |= DRIVE_16MA;
            else
                output[0x0d] |= eeprom->group2_drive;
            if (eeprom->group2_schmitt == IS_SCHMITT)
                output[0x0d] |= IS_SCHMITT;
            if (eeprom->group2_slew == SLOW_SLEW)
                output[0x0d] |= SLOW_SLEW;

            if (eeprom->group3_drive > DRIVE_16MA)
                output[0x0d] |= DRIVE_16MA<<4;
            else
                output[0x0d] |= eeprom->group3_drive<<4;
            if (eeprom->group3_schmitt == IS_SCHMITT)
                output[0x0d] |= IS_SCHMITT<<4;
            if (eeprom->group3_slew == SLOW_SLEW)
                output[0x0d] |= SLOW_SLEW<<4;

            output[0x18] = eeprom->chip;

            break;
        case TYPE_232H:
            output[0x00] = type2bit(eeprom->channel_a_type, TYPE_232H);
            if ( eeprom->channel_a_driver == DRIVER_VCP)
                output[0x00] |= DRIVER_VCPH;
            else
                output[0x00] &= ~DRIVER_VCPH;
            if (eeprom->powersave)
                output[0x01] |= POWER_SAVE_DISABLE_H;
            else
                output[0x01] &= ~POWER_SAVE_DISABLE_H;
            if (eeprom->clock_polarity)
                output[0x01] |= FT1284_CLK_IDLE_STATE;
            else
                output[0x01] &= ~FT1284_CLK_IDLE_STATE;
            if (eeprom->data_order)
                output[0x01] |= FT1284_DATA_LSB;
            else
                output[0x01] &= ~FT1284_DATA_LSB;
            if (eeprom->flow_control)
                output[0x01] |= FT1284_FLOW_CONTROL;
            else
                output[0x01] &= ~FT1284_FLOW_CONTROL;
            if (eeprom->group0_drive > DRIVE_16MA)
                output[0x0c] |= DRIVE_16MA;
            else
                output[0x0c] |= eeprom->group0_drive;
            if (eeprom->group0_schmitt == IS_SCHMITT)
                output[0x0c] |= IS_SCHMITT;
            if (eeprom->group0_slew == SLOW_SLEW)
                output[0x0c] |= SLOW_SLEW;

            if (eeprom->group1_drive > DRIVE_16MA)
                output[0x0d] |= DRIVE_16MA;
            else
                output[0x0d] |= eeprom->group1_drive;
            if (eeprom->group1_schmitt == IS_SCHMITT)
                output[0x0d] |= IS_SCHMITT;
            if (eeprom->group1_slew == SLOW_SLEW)
                output[0x0d] |= SLOW_SLEW;

            set_ft232h_cbus(eeprom, output);

            output[0x1e] = eeprom->chip;
            fprintf(stderr,"FIXME: Build FT232H specific EEPROM settings\n");
            break;
              
    }

    // calculate checksum
    checksum = 0xAAAA;

    for (i = 0; i < eeprom->size/2-1; i++)
    {
        value = output[i*2];
        value += output[(i*2)+1] << 8;

        checksum = value^checksum;
        checksum = (checksum << 1) | (checksum >> 15);
    }

    output[eeprom->size-2] = checksum;
    output[eeprom->size-1] = checksum >> 8;

    return user_area_size;
}
/* Decode the encoded EEPROM field for the FTDI Mode into a value for the abstracted 
 * EEPROM structure
 *
 * FTD2XX doesn't allow to set multiple bits in the interface mode bitfield, and so do we
 */
static unsigned char bit2type(unsigned char bits)
{
    switch (bits)
    {
    case   0: return CHANNEL_IS_UART;
    case   1: return CHANNEL_IS_FIFO;
    case   2: return CHANNEL_IS_OPTO;
    case   4: return CHANNEL_IS_CPU;
    case   8: return CHANNEL_IS_FT1284;
    default:
        fprintf(stderr," Unexpected value %d for Hardware Interface type\n",
                bits);
    }
    return 0;
}
int ftdi_eeprom_decode(struct ftdi_context *ftdi, int verbose)
{
    unsigned char i, j;
    unsigned short checksum, eeprom_checksum, value;
    unsigned char manufacturer_size = 0, product_size = 0, serial_size = 0;
    int eeprom_size;
    struct ftdi_eeprom *eeprom;
    unsigned char *buf = ftdi->eeprom->buf;
    int release;

    if (ftdi == NULL)
        ftdi_error_return(-1,"No context");
    if (ftdi->eeprom == NULL)
        ftdi_error_return(-1,"No eeprom structure");

    eeprom = ftdi->eeprom;
    eeprom_size = eeprom->size;

    // Addr 02: Vendor ID
    eeprom->vendor_id = buf[0x02] + (buf[0x03] << 8);

    // Addr 04: Product ID
    eeprom->product_id = buf[0x04] + (buf[0x05] << 8);

    release = buf[0x06] + (buf[0x07]<<8);

    // Addr 08: Config descriptor
    // Bit 7: always 1
    // Bit 6: 1 if this device is self powered, 0 if bus powered
    // Bit 5: 1 if this device uses remote wakeup
    eeprom->self_powered = buf[0x08] & 0x40;
    eeprom->remote_wakeup = buf[0x08] & 0x20;

    // Addr 09: Max power consumption: max power = value * 2 mA
    eeprom->max_power = MAX_POWER_MILLIAMP_PER_UNIT * buf[0x09];

    // Addr 0A: Chip configuration
    // Bit 7: 0 - reserved
    // Bit 6: 0 - reserved
    // Bit 5: 0 - reserved
    // Bit 4: 1 - Change USB version on BM and 2232C
    // Bit 3: 1 - Use the serial number string
    // Bit 2: 1 - Enable suspend pull downs for lower power
    // Bit 1: 1 - Out EndPoint is Isochronous
    // Bit 0: 1 - In EndPoint is Isochronous
    //
    eeprom->in_is_isochronous  = buf[0x0A]&0x01;
    eeprom->out_is_isochronous = buf[0x0A]&0x02;
    eeprom->suspend_pull_downs = buf[0x0A]&0x04;
    eeprom->use_serial         = (buf[0x0A] & USE_SERIAL_NUM)?1:0;
    eeprom->use_usb_version    = buf[0x0A] & USE_USB_VERSION_BIT;

    // Addr 0C: USB version low byte when 0x0A
    // Addr 0D: USB version high byte when 0x0A
    eeprom->usb_version = buf[0x0C] + (buf[0x0D] << 8);

    // Addr 0E: Offset of the manufacturer string + 0x80, calculated later
    // Addr 0F: Length of manufacturer string
    manufacturer_size = buf[0x0F]/2;
    if (eeprom->manufacturer)
        free(eeprom->manufacturer);
    if (manufacturer_size > 0)
    {
        eeprom->manufacturer = malloc(manufacturer_size);
        if (eeprom->manufacturer)
        {
            // Decode manufacturer
            i = buf[0x0E] & (eeprom_size -1); // offset
            for (j=0;j<manufacturer_size-1;j++)
            {
                eeprom->manufacturer[j] = buf[2*j+i+2];
            }
            eeprom->manufacturer[j] = '\0';
        }
    }
    else eeprom->manufacturer = NULL;

    // Addr 10: Offset of the product string + 0x80, calculated later
    // Addr 11: Length of product string
    if (eeprom->product)
        free(eeprom->product);
    product_size = buf[0x11]/2;
    if (product_size > 0)
    {
        eeprom->product = malloc(product_size);
        if (eeprom->product)
        {
            // Decode product name
            i = buf[0x10] & (eeprom_size -1); // offset
            for (j=0;j<product_size-1;j++)
            {
                eeprom->product[j] = buf[2*j+i+2];
            }
            eeprom->product[j] = '\0';
        }
    }
    else eeprom->product = NULL;

    // Addr 12: Offset of the serial string + 0x80, calculated later
    // Addr 13: Length of serial string
    if (eeprom->serial)
        free(eeprom->serial);
    serial_size = buf[0x13]/2;
    if (serial_size > 0)
    {
        eeprom->serial = malloc(serial_size);
        if (eeprom->serial)
        {
            // Decode serial
            i = buf[0x12] & (eeprom_size -1); // offset
            for (j=0;j<serial_size-1;j++)
            {
                eeprom->serial[j] = buf[2*j+i+2];
            }
            eeprom->serial[j] = '\0';
        }
    }
    else eeprom->serial = NULL;

    // verify checksum
    checksum = 0xAAAA;

    for (i = 0; i < eeprom_size/2-1; i++)
    {
        value = buf[i*2];
        value += buf[(i*2)+1] << 8;

        checksum = value^checksum;
        checksum = (checksum << 1) | (checksum >> 15);
    }

    eeprom_checksum = buf[eeprom_size-2] + (buf[eeprom_size-1] << 8);

    if (eeprom_checksum != checksum)
    {
        fprintf(stderr, "Checksum Error: %04x %04x\n", checksum, eeprom_checksum);
        ftdi_error_return(-1,"EEPROM checksum error");
    }

    eeprom->channel_a_type   = 0;
    if ((ftdi->type == TYPE_AM) || (ftdi->type == TYPE_BM))
    {
        eeprom->chip = -1;
    }
    else if (ftdi->type == TYPE_2232C)
    {
        eeprom->channel_a_type   = bit2type(buf[0x00] & 0x7);
        eeprom->channel_a_driver = buf[0x00] & DRIVER_VCP;
        eeprom->high_current_a   = buf[0x00] & HIGH_CURRENT_DRIVE;
        eeprom->channel_b_type   = buf[0x01] & 0x7;
        eeprom->channel_b_driver = buf[0x01] & DRIVER_VCP;
        eeprom->high_current_b   = buf[0x01] & HIGH_CURRENT_DRIVE;
        eeprom->chip = buf[0x14];
    }
    else if (ftdi->type == TYPE_R)
    {
        /* TYPE_R flags D2XX, not VCP as all others*/
        eeprom->channel_a_driver = ~buf[0x00] & DRIVER_VCP;
        eeprom->high_current     = buf[0x00] & HIGH_CURRENT_DRIVE_R;
        if ( (buf[0x01]&0x40) != 0x40)
            fprintf(stderr,
                    "TYPE_R EEPROM byte[0x01] Bit 6 unexpected Endpoint size."
                    " If this happened with the\n"
                    " EEPROM programmed by FTDI tools, please report "
                    "to libftdi@developer.intra2net.com\n");

        eeprom->chip = buf[0x16];
        // Addr 0B: Invert data lines
        // Works only on FT232R, not FT245R, but no way to distinguish
        eeprom->invert = buf[0x0B];
        // Addr 14: CBUS function: CBUS0, CBUS1
        // Addr 15: CBUS function: CBUS2, CBUS3
        // Addr 16: CBUS function: CBUS5
        eeprom->cbus_function[0] = buf[0x14] & 0x0f;
        eeprom->cbus_function[1] = (buf[0x14] >> 4) & 0x0f;
        eeprom->cbus_function[2] = buf[0x15] & 0x0f;
        eeprom->cbus_function[3] = (buf[0x15] >> 4) & 0x0f;
        eeprom->cbus_function[4] = buf[0x16] & 0x0f;
    }
    else if ((ftdi->type == TYPE_2232H) || (ftdi->type == TYPE_4232H))
    {
        eeprom->channel_a_driver = buf[0x00] & DRIVER_VCP;
        eeprom->channel_b_driver = buf[0x01] & DRIVER_VCP;

        if (ftdi->type == TYPE_2232H)
        {
            eeprom->channel_a_type   = bit2type(buf[0x00] & 0x7);
            eeprom->channel_b_type   = bit2type(buf[0x01] & 0x7);
            eeprom->suspend_dbus7    = buf[0x01] & SUSPEND_DBUS7_BIT;
        }
        else
        {
            eeprom->channel_c_driver = (buf[0x00] >> 4) & DRIVER_VCP;
            eeprom->channel_d_driver = (buf[0x01] >> 4) & DRIVER_VCP;
            eeprom->channel_a_rs485enable = buf[0x0b] & (CHANNEL_IS_RS485 << 0);
            eeprom->channel_b_rs485enable = buf[0x0b] & (CHANNEL_IS_RS485 << 1);
            eeprom->channel_c_rs485enable = buf[0x0b] & (CHANNEL_IS_RS485 << 2);
            eeprom->channel_d_rs485enable = buf[0x0b] & (CHANNEL_IS_RS485 << 3);
        }

        eeprom->chip = buf[0x18];
        eeprom->group0_drive   =  buf[0x0c]       & DRIVE_16MA;
        eeprom->group0_schmitt =  buf[0x0c]       & IS_SCHMITT;
        eeprom->group0_slew    =  buf[0x0c]       & SLOW_SLEW;
        eeprom->group1_drive   = (buf[0x0c] >> 4) & 0x3;
        eeprom->group1_schmitt = (buf[0x0c] >> 4) & IS_SCHMITT;
        eeprom->group1_slew    = (buf[0x0c] >> 4) & SLOW_SLEW;
        eeprom->group2_drive   =  buf[0x0d]       & DRIVE_16MA;
        eeprom->group2_schmitt =  buf[0x0d]       & IS_SCHMITT;
        eeprom->group2_slew    =  buf[0x0d]       & SLOW_SLEW;
        eeprom->group3_drive   = (buf[0x0d] >> 4) & DRIVE_16MA;
        eeprom->group3_schmitt = (buf[0x0d] >> 4) & IS_SCHMITT;
        eeprom->group3_slew    = (buf[0x0d] >> 4) & SLOW_SLEW;
    }
    else if (ftdi->type == TYPE_232H)
    {
        int i;

        eeprom->channel_a_type   = buf[0x00] & 0xf;
        eeprom->channel_a_driver = (buf[0x00] & DRIVER_VCPH)?DRIVER_VCP:0;
        eeprom->clock_polarity =  buf[0x01]       & FT1284_CLK_IDLE_STATE;
        eeprom->data_order     =  buf[0x01]       & FT1284_DATA_LSB;
        eeprom->flow_control   =  buf[0x01]       & FT1284_FLOW_CONTROL;
        eeprom->powersave      =  buf[0x01]       & POWER_SAVE_DISABLE_H;
        eeprom->group0_drive   =  buf[0x0c]       & DRIVE_16MA;
        eeprom->group0_schmitt =  buf[0x0c]       & IS_SCHMITT;
        eeprom->group0_slew    =  buf[0x0c]       & SLOW_SLEW;
        eeprom->group1_drive   =  buf[0x0d]       & DRIVE_16MA;
        eeprom->group1_schmitt =  buf[0x0d]       & IS_SCHMITT;
        eeprom->group1_slew    =  buf[0x0d]       & SLOW_SLEW;

        for(i=0; i<5; i++)
        {
            eeprom->cbus_function[2*i  ] =  buf[0x18+i] & 0x0f;
            eeprom->cbus_function[2*i+1] = (buf[0x18+i] >> 4) & 0x0f;
        }
        eeprom->chip = buf[0x1e];
        /*FIXME: Decipher more values*/
    }

    if (verbose)
    {
        char *channel_mode[] = {"UART", "FIFO", "CPU", "OPTO", "FT1284"};
        fprintf(stdout, "VID:     0x%04x\n",eeprom->vendor_id);
        fprintf(stdout, "PID:     0x%04x\n",eeprom->product_id);
        fprintf(stdout, "Release: 0x%04x\n",release);

        if (eeprom->self_powered)
            fprintf(stdout, "Self-Powered%s", (eeprom->remote_wakeup)?", USB Remote Wake Up\n":"\n");
        else
            fprintf(stdout, "Bus Powered: %3d mA%s", eeprom->max_power,
                    (eeprom->remote_wakeup)?" USB Remote Wake Up\n":"\n");
        if (eeprom->manufacturer)
            fprintf(stdout, "Manufacturer: %s\n",eeprom->manufacturer);
        if (eeprom->product)
            fprintf(stdout, "Product:      %s\n",eeprom->product);
        if (eeprom->serial)
            fprintf(stdout, "Serial:       %s\n",eeprom->serial);
        fprintf(stdout,     "Checksum      : %04x\n", checksum);
        if (ftdi->type == TYPE_R)
            fprintf(stdout,     "Internal EEPROM\n");
        else if (eeprom->chip >= 0x46)
            fprintf(stdout,     "Attached EEPROM: 93x%02x\n", eeprom->chip);
        if (eeprom->suspend_dbus7)
            fprintf(stdout, "Suspend on DBUS7\n");
        if (eeprom->suspend_pull_downs)
            fprintf(stdout, "Pull IO pins low during suspend\n");
        if(eeprom->powersave)
        {
            if(ftdi->type >= TYPE_232H)
                fprintf(stdout,"Enter low power state on ACBUS7\n");
        } 
        if (eeprom->remote_wakeup)
            fprintf(stdout, "Enable Remote Wake Up\n");
        fprintf(stdout, "PNP: %d\n",(eeprom->is_not_pnp)?0:1);
        if (ftdi->type >= TYPE_2232C)
            fprintf(stdout,"Channel A has Mode %s%s%s\n",
                    channel_mode[eeprom->channel_a_type],
                    (eeprom->channel_a_driver)?" VCP":"",
                    (eeprom->high_current_a)?" High Current IO":"");
        if (ftdi->type >= TYPE_232H)
        {
            fprintf(stdout,"FT1284 Mode Clock is idle %s, %s first, %sFlow Control\n",
                    (eeprom->clock_polarity)?"HIGH":"LOW",
                    (eeprom->data_order)?"LSB":"MSB",
                    (eeprom->flow_control)?"":"No ");
        }        
        if ((ftdi->type >= TYPE_2232C) && (ftdi->type != TYPE_R) && (ftdi->type != TYPE_232H))
            fprintf(stdout,"Channel B has Mode %s%s%s\n",
                    channel_mode[eeprom->channel_b_type],
                    (eeprom->channel_b_driver)?" VCP":"",
                    (eeprom->high_current_b)?" High Current IO":"");
        if (((ftdi->type == TYPE_BM) || (ftdi->type == TYPE_2232C)) &&
                eeprom->use_usb_version == USE_USB_VERSION_BIT)
            fprintf(stdout,"Use explicit USB Version %04x\n",eeprom->usb_version);

        if ((ftdi->type == TYPE_2232H) || (ftdi->type == TYPE_4232H))
        {
            fprintf(stdout,"%s has %d mA drive%s%s\n",
                    (ftdi->type == TYPE_2232H)?"AL":"A",
                    (eeprom->group0_drive+1) *4,
                    (eeprom->group0_schmitt)?" Schmitt Input":"",
                    (eeprom->group0_slew)?" Slow Slew":"");
            fprintf(stdout,"%s has %d mA drive%s%s\n",
                    (ftdi->type == TYPE_2232H)?"AH":"B",
                    (eeprom->group1_drive+1) *4,
                    (eeprom->group1_schmitt)?" Schmitt Input":"",
                    (eeprom->group1_slew)?" Slow Slew":"");
            fprintf(stdout,"%s has %d mA drive%s%s\n",
                    (ftdi->type == TYPE_2232H)?"BL":"C",
                    (eeprom->group2_drive+1) *4,
                    (eeprom->group2_schmitt)?" Schmitt Input":"",
                    (eeprom->group2_slew)?" Slow Slew":"");
            fprintf(stdout,"%s has %d mA drive%s%s\n",
                    (ftdi->type == TYPE_2232H)?"BH":"D",
                    (eeprom->group3_drive+1) *4,
                    (eeprom->group3_schmitt)?" Schmitt Input":"",
                    (eeprom->group3_slew)?" Slow Slew":"");
        }
        else if (ftdi->type == TYPE_232H)
        {
            int i;
            char *cbush_mux[] = {"TRISTATE","RXLED","TXLED", "TXRXLED","PWREN",
                                "SLEEP","DRIVE_0","DRIVE_1","IOMODE","TXDEN",
                                "CLK30","CLK15","CLK7_5"
                               };
            fprintf(stdout,"ACBUS has %d mA drive%s%s\n",
                    (eeprom->group0_drive+1) *4,
                    (eeprom->group0_schmitt)?" Schmitt Input":"",
                    (eeprom->group0_slew)?" Slow Slew":"");
            fprintf(stdout,"ADBUS has %d mA drive%s%s\n",
                    (eeprom->group1_drive+1) *4,
                    (eeprom->group1_schmitt)?" Schmitt Input":"",
                    (eeprom->group1_slew)?" Slow Slew":"");
            for (i=0; i<10; i++)
            {
                if (eeprom->cbus_function[i]<= CBUSH_CLK7_5 )
                    fprintf(stdout,"C%d Function: %s\n", i,
                            cbush_mux[eeprom->cbus_function[i]]);
            }
        }

        if (ftdi->type == TYPE_R)
        {
            char *cbus_mux[] = {"TXDEN","PWREN","RXLED", "TXLED","TX+RXLED",
                                "SLEEP","CLK48","CLK24","CLK12","CLK6",
                                "IOMODE","BB_WR","BB_RD"
                               };
            char *cbus_BB[] = {"RXF","TXE","RD", "WR"};

            if (eeprom->invert)
            {
                char *r_bits[] = {"TXD","RXD","RTS", "CTS","DTR","DSR","DCD","RI"};
                fprintf(stdout,"Inverted bits:");
                for (i=0; i<8; i++)
                    if ((eeprom->invert & (1<<i)) == (1<<i))
                        fprintf(stdout," %s",r_bits[i]);
                fprintf(stdout,"\n");
            }
            for (i=0; i<5; i++)
            {
                if (eeprom->cbus_function[i]<CBUS_BB)
                    fprintf(stdout,"C%d Function: %s\n", i,
                            cbus_mux[eeprom->cbus_function[i]]);
                else
                {
                    if (i < 4)
                        /* Running MPROG show that C0..3 have fixed function Synchronous
                           Bit Bang mode */
                        fprintf(stdout,"C%d BB Function: %s\n", i,
                                cbus_BB[i]);
                    else
                        fprintf(stdout, "Unknown CBUS mode. Might be special mode?\n");
                }
            }
        }
    }
    return 0;
}

int ftdi_get_eeprom_value(struct ftdi_context *ftdi, enum ftdi_eeprom_value value_name, int* value)
{
    switch (value_name)
    {
        case VENDOR_ID:
            *value = ftdi->eeprom->vendor_id;
            break;
        case PRODUCT_ID:
            *value = ftdi->eeprom->product_id;
            break;
        case SELF_POWERED:
            *value = ftdi->eeprom->self_powered;
            break;
        case REMOTE_WAKEUP:
            *value = ftdi->eeprom->remote_wakeup;
            break;
        case IS_NOT_PNP:
            *value = ftdi->eeprom->is_not_pnp;
            break;
        case SUSPEND_DBUS7:
            *value = ftdi->eeprom->suspend_dbus7;
            break;
        case IN_IS_ISOCHRONOUS:
            *value = ftdi->eeprom->in_is_isochronous;
            break;
        case OUT_IS_ISOCHRONOUS:
            *value = ftdi->eeprom->out_is_isochronous;
            break;
        case SUSPEND_PULL_DOWNS:
            *value = ftdi->eeprom->suspend_pull_downs;
            break;
        case USE_SERIAL:
            *value = ftdi->eeprom->use_serial;
            break;
        case USB_VERSION:
            *value = ftdi->eeprom->usb_version;
            break;
        case USE_USB_VERSION:
            *value = ftdi->eeprom->use_usb_version;
            break;
        case MAX_POWER:
            *value = ftdi->eeprom->max_power;
            break;
        case CHANNEL_A_TYPE:
            *value = ftdi->eeprom->channel_a_type;
            break;
        case CHANNEL_B_TYPE:
            *value = ftdi->eeprom->channel_b_type;
            break;
        case CHANNEL_A_DRIVER:
            *value = ftdi->eeprom->channel_a_driver;
            break;
        case CHANNEL_B_DRIVER:
            *value = ftdi->eeprom->channel_b_driver;
            break;
        case CHANNEL_C_DRIVER:
            *value = ftdi->eeprom->channel_c_driver;
            break;
        case CHANNEL_D_DRIVER:
            *value = ftdi->eeprom->channel_d_driver;
            break;
        case CHANNEL_A_RS485:
            *value = ftdi->eeprom->channel_a_rs485enable;
            break;
        case CHANNEL_B_RS485:
            *value = ftdi->eeprom->channel_b_rs485enable;
            break;
        case CHANNEL_C_RS485:
            *value = ftdi->eeprom->channel_c_rs485enable;
            break;
        case CHANNEL_D_RS485:
            *value = ftdi->eeprom->channel_d_rs485enable;
            break;
        case CBUS_FUNCTION_0:
            *value = ftdi->eeprom->cbus_function[0];
            break;
        case CBUS_FUNCTION_1:
            *value = ftdi->eeprom->cbus_function[1];
            break;
        case CBUS_FUNCTION_2:
            *value = ftdi->eeprom->cbus_function[2];
            break;
        case CBUS_FUNCTION_3:
            *value = ftdi->eeprom->cbus_function[3];
            break;
        case CBUS_FUNCTION_4:
            *value = ftdi->eeprom->cbus_function[4];
            break;
        case CBUS_FUNCTION_5:
            *value = ftdi->eeprom->cbus_function[5];
            break;
        case CBUS_FUNCTION_6:
            *value = ftdi->eeprom->cbus_function[6];
            break;
        case CBUS_FUNCTION_7:
            *value = ftdi->eeprom->cbus_function[7];
            break;
        case CBUS_FUNCTION_8:
            *value = ftdi->eeprom->cbus_function[8];
            break;
        case CBUS_FUNCTION_9:
            *value = ftdi->eeprom->cbus_function[8];
            break;
        case HIGH_CURRENT:
            *value = ftdi->eeprom->high_current;
            break;
        case HIGH_CURRENT_A:
            *value = ftdi->eeprom->high_current_a;
            break;
        case HIGH_CURRENT_B:
            *value = ftdi->eeprom->high_current_b;
            break;
        case INVERT:
            *value = ftdi->eeprom->invert;
            break;
        case GROUP0_DRIVE:
            *value = ftdi->eeprom->group0_drive;
            break;
        case GROUP0_SCHMITT:
            *value = ftdi->eeprom->group0_schmitt;
            break;
        case GROUP0_SLEW:
            *value = ftdi->eeprom->group0_slew;
            break;
        case GROUP1_DRIVE:
            *value = ftdi->eeprom->group1_drive;
            break;
        case GROUP1_SCHMITT:
            *value = ftdi->eeprom->group1_schmitt;
            break;
        case GROUP1_SLEW:
            *value = ftdi->eeprom->group1_slew;
            break;
        case GROUP2_DRIVE:
            *value = ftdi->eeprom->group2_drive;
            break;
        case GROUP2_SCHMITT:
            *value = ftdi->eeprom->group2_schmitt;
            break;
        case GROUP2_SLEW:
            *value = ftdi->eeprom->group2_slew;
            break;
        case GROUP3_DRIVE:
            *value = ftdi->eeprom->group3_drive;
            break;
        case GROUP3_SCHMITT:
            *value = ftdi->eeprom->group3_schmitt;
            break;
        case GROUP3_SLEW:
            *value = ftdi->eeprom->group3_slew;
            break;
         case POWER_SAVE:
            *value = ftdi->eeprom->powersave;
            break;
          case CLOCK_POLARITY:
            *value = ftdi->eeprom->clock_polarity;
            break;
         case DATA_ORDER:
            *value = ftdi->eeprom->data_order;
            break;
         case FLOW_CONTROL:
            *value = ftdi->eeprom->flow_control;
            break;
       case CHIP_TYPE:
            *value = ftdi->eeprom->chip;
            break;
        case CHIP_SIZE:
            *value = ftdi->eeprom->size;
            break;
        default:
            ftdi_error_return(-1, "Request for unknown EEPROM value");
    }
    return 0;
}

int ftdi_set_eeprom_value(struct ftdi_context *ftdi, enum ftdi_eeprom_value value_name, int value)
{
    switch (value_name)
    {
        case VENDOR_ID:
            ftdi->eeprom->vendor_id = value;
            break;
        case PRODUCT_ID:
            ftdi->eeprom->product_id = value;
            break;
        case SELF_POWERED:
            ftdi->eeprom->self_powered = value;
            break;
        case REMOTE_WAKEUP:
            ftdi->eeprom->remote_wakeup = value;
            break;
        case IS_NOT_PNP:
            ftdi->eeprom->is_not_pnp = value;
            break;
        case SUSPEND_DBUS7:
            ftdi->eeprom->suspend_dbus7 = value;
            break;
        case IN_IS_ISOCHRONOUS:
            ftdi->eeprom->in_is_isochronous = value;
            break;
        case OUT_IS_ISOCHRONOUS:
            ftdi->eeprom->out_is_isochronous = value;
            break;
        case SUSPEND_PULL_DOWNS:
            ftdi->eeprom->suspend_pull_downs = value;
            break;
        case USE_SERIAL:
            ftdi->eeprom->use_serial = value;
            break;
        case USB_VERSION:
            ftdi->eeprom->usb_version = value;
            break;
        case USE_USB_VERSION:
            ftdi->eeprom->use_usb_version = value;
            break;
        case MAX_POWER:
            ftdi->eeprom->max_power = value;
            break;
        case CHANNEL_A_TYPE:
            ftdi->eeprom->channel_a_type = value;
            break;
        case CHANNEL_B_TYPE:
            ftdi->eeprom->channel_b_type = value;
            break;
        case CHANNEL_A_DRIVER:
            ftdi->eeprom->channel_a_driver = value;
            break;
        case CHANNEL_B_DRIVER:
            ftdi->eeprom->channel_b_driver = value;
            break;
        case CHANNEL_C_DRIVER:
            ftdi->eeprom->channel_c_driver = value;
            break;
        case CHANNEL_D_DRIVER:
            ftdi->eeprom->channel_d_driver = value;
            break;
        case CHANNEL_A_RS485:
            ftdi->eeprom->channel_a_rs485enable = value;
            break;
        case CHANNEL_B_RS485:
            ftdi->eeprom->channel_b_rs485enable = value;
            break;
        case CHANNEL_C_RS485:
            ftdi->eeprom->channel_c_rs485enable = value;
            break;
        case CHANNEL_D_RS485:
            ftdi->eeprom->channel_d_rs485enable = value;
            break;
        case CBUS_FUNCTION_0:
            ftdi->eeprom->cbus_function[0] = value;
            break;
        case CBUS_FUNCTION_1:
            ftdi->eeprom->cbus_function[1] = value;
            break;
        case CBUS_FUNCTION_2:
            ftdi->eeprom->cbus_function[2] = value;
            break;
        case CBUS_FUNCTION_3:
            ftdi->eeprom->cbus_function[3] = value;
            break;
        case CBUS_FUNCTION_4:
            ftdi->eeprom->cbus_function[4] = value;
            break;
        case CBUS_FUNCTION_5:
            ftdi->eeprom->cbus_function[5] = value;
            break;
        case CBUS_FUNCTION_6:
            ftdi->eeprom->cbus_function[6] = value;
            break;
        case CBUS_FUNCTION_7:
            ftdi->eeprom->cbus_function[7] = value;
            break;
        case CBUS_FUNCTION_8:
            ftdi->eeprom->cbus_function[8] = value;
            break;
        case CBUS_FUNCTION_9:
            ftdi->eeprom->cbus_function[9] = value;
            break;
        case HIGH_CURRENT:
            ftdi->eeprom->high_current = value;
            break;
        case HIGH_CURRENT_A:
            ftdi->eeprom->high_current_a = value;
            break;
        case HIGH_CURRENT_B:
            ftdi->eeprom->high_current_b = value;
            break;
        case INVERT:
            ftdi->eeprom->invert = value;
            break;
        case GROUP0_DRIVE:
            ftdi->eeprom->group0_drive = value;
            break;
        case GROUP0_SCHMITT:
            ftdi->eeprom->group0_schmitt = value;
            break;
        case GROUP0_SLEW:
            ftdi->eeprom->group0_slew = value;
            break;
        case GROUP1_DRIVE:
            ftdi->eeprom->group1_drive = value;
            break;
        case GROUP1_SCHMITT:
            ftdi->eeprom->group1_schmitt = value;
            break;
        case GROUP1_SLEW:
            ftdi->eeprom->group1_slew = value;
            break;
        case GROUP2_DRIVE:
            ftdi->eeprom->group2_drive = value;
            break;
        case GROUP2_SCHMITT:
            ftdi->eeprom->group2_schmitt = value;
            break;
        case GROUP2_SLEW:
            ftdi->eeprom->group2_slew = value;
            break;
        case GROUP3_DRIVE:
            ftdi->eeprom->group3_drive = value;
            break;
        case GROUP3_SCHMITT:
            ftdi->eeprom->group3_schmitt = value;
            break;
        case GROUP3_SLEW:
            ftdi->eeprom->group3_slew = value;
            break;
        case CHIP_TYPE:
            ftdi->eeprom->chip = value;
            break;
         case POWER_SAVE:
            ftdi->eeprom->powersave = value;
            break;
         case CLOCK_POLARITY:
            ftdi->eeprom->clock_polarity = value;
            break;
         case DATA_ORDER:
            ftdi->eeprom->data_order = value;
            break;
         case FLOW_CONTROL:
            ftdi->eeprom->flow_control = value;
            break;
        case CHIP_SIZE:
            ftdi_error_return(-2, "EEPROM Value can't be changed");
        default :
            ftdi_error_return(-1, "Request to unknown EEPROM value");
    }
    return 0;
}

int ftdi_get_eeprom_buf(struct ftdi_context *ftdi, unsigned char * buf, int size)
{
    if (!ftdi || !(ftdi->eeprom))
        ftdi_error_return(-1, "No appropriate structure");

    if (!buf || size < ftdi->eeprom->size)
        ftdi_error_return(-1, "Not enough room to store eeprom");

    // Only copy up to FTDI_MAX_EEPROM_SIZE bytes
    if (size > FTDI_MAX_EEPROM_SIZE)
        size = FTDI_MAX_EEPROM_SIZE;

    memcpy(buf, ftdi->eeprom->buf, size);

    return 0;
}

int ftdi_set_eeprom_buf(struct ftdi_context *ftdi, const unsigned char * buf, int size)
{
    if (!ftdi || !(ftdi->eeprom) || !buf)
        ftdi_error_return(-1, "No appropriate structure");

    // Only copy up to FTDI_MAX_EEPROM_SIZE bytes
    if (size > FTDI_MAX_EEPROM_SIZE)
        size = FTDI_MAX_EEPROM_SIZE;

    memcpy(ftdi->eeprom->buf, buf, size);

    return 0;
}

int ftdi_read_eeprom_location (struct ftdi_context *ftdi, int eeprom_addr, unsigned short *eeprom_val)
{
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_EEPROM_REQUEST, 0, eeprom_addr, (unsigned char *)eeprom_val, 2, ftdi->usb_read_timeout) != 2)
        ftdi_error_return(-1, "reading eeprom failed");

    return 0;
}

int ftdi_read_eeprom(struct ftdi_context *ftdi)
{
    int i;
    unsigned char *buf;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");
    buf = ftdi->eeprom->buf;

    for (i = 0; i < FTDI_MAX_EEPROM_SIZE/2; i++)
    {
        if (libusb_control_transfer(
                    ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE,SIO_READ_EEPROM_REQUEST, 0, i,
                    buf+(i*2), 2, ftdi->usb_read_timeout) != 2)
            ftdi_error_return(-1, "reading eeprom failed");
    }

    if (ftdi->type == TYPE_R)
        ftdi->eeprom->size = 0x80;
    /*    Guesses size of eeprom by comparing halves
          - will not work with blank eeprom */
    else if (strrchr((const char *)buf, 0xff) == ((const char *)buf +FTDI_MAX_EEPROM_SIZE -1))
        ftdi->eeprom->size = -1;
    else if (memcmp(buf,&buf[0x80],0x80) == 0)
        ftdi->eeprom->size = 0x80;
    else if (memcmp(buf,&buf[0x40],0x40) == 0)
        ftdi->eeprom->size = 0x40;
    else
        ftdi->eeprom->size = 0x100;
    return 0;
}

/*
    ftdi_read_chipid_shift does the bitshift operation needed for the FTDIChip-ID
    Function is only used internally
    \internal
*/
static unsigned char ftdi_read_chipid_shift(unsigned char value)
{
    return ((value & 1) << 1) |
           ((value & 2) << 5) |
           ((value & 4) >> 2) |
           ((value & 8) << 4) |
           ((value & 16) >> 1) |
           ((value & 32) >> 1) |
           ((value & 64) >> 4) |
           ((value & 128) >> 2);
}

int ftdi_read_chipid(struct ftdi_context *ftdi, unsigned int *chipid)
{
    unsigned int a = 0, b = 0;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_EEPROM_REQUEST, 0, 0x43, (unsigned char *)&a, 2, ftdi->usb_read_timeout) == 2)
    {
        a = a << 8 | a >> 8;
        if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_IN_REQTYPE, SIO_READ_EEPROM_REQUEST, 0, 0x44, (unsigned char *)&b, 2, ftdi->usb_read_timeout) == 2)
        {
            b = b << 8 | b >> 8;
            a = (a << 16) | (b & 0xFFFF);
            a = ftdi_read_chipid_shift(a) | ftdi_read_chipid_shift(a>>8)<<8
                | ftdi_read_chipid_shift(a>>16)<<16 | ftdi_read_chipid_shift(a>>24)<<24;
            *chipid = a ^ 0xa5f0f7d1;
            return 0;
        }
    }

    ftdi_error_return(-1, "read of FTDIChip-ID failed");
}

int ftdi_write_eeprom_location(struct ftdi_context *ftdi, int eeprom_addr,
                               unsigned short eeprom_val)
{
    int chip_type_location;
    unsigned short chip_type;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (eeprom_addr <0x80)
        ftdi_error_return(-2, "Invalid access to checksum protected area  below 0x80");


    switch (ftdi->type)
    {
        case TYPE_BM:
        case  TYPE_2232C:
            chip_type_location = 0x14;
            break;
        case TYPE_2232H:
        case TYPE_4232H:
            chip_type_location = 0x18;
            break;
        case TYPE_232H:
            chip_type_location = 0x1e;
            break;
        default:
            ftdi_error_return(-4, "Device can't access unprotected area");
    }

    if (ftdi_read_eeprom_location( ftdi, chip_type_location>>1, &chip_type))
        ftdi_error_return(-5, "Reading failed failed");
    fprintf(stderr," loc 0x%04x val 0x%04x\n", chip_type_location,chip_type);
    if ((chip_type & 0xff) != 0x66)
    {
        ftdi_error_return(-6, "EEPROM is not of 93x66");
    }

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_WRITE_EEPROM_REQUEST, eeprom_val, eeprom_addr,
                                NULL, 0, ftdi->usb_write_timeout) != 0)
        ftdi_error_return(-1, "unable to write eeprom");

    return 0;
}

int ftdi_write_eeprom(struct ftdi_context *ftdi)
{
    unsigned short usb_val, status;
    int i, ret;
    unsigned char *eeprom;

    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if(ftdi->eeprom->initialized_for_connected_device == 0)
        ftdi_error_return(-3, "EEPROM not initialized for the connected device");

    eeprom = ftdi->eeprom->buf;

    /* These commands were traced while running MProg */
    if ((ret = ftdi_usb_reset(ftdi)) != 0)
        return ret;
    if ((ret = ftdi_poll_modem_status(ftdi, &status)) != 0)
        return ret;
    if ((ret = ftdi_set_latency_timer(ftdi, 0x77)) != 0)
        return ret;

    for (i = 0; i < ftdi->eeprom->size/2; i++)
    {
        usb_val = eeprom[i*2];
        usb_val += eeprom[(i*2)+1] << 8;
        if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                    SIO_WRITE_EEPROM_REQUEST, usb_val, i,
                                    NULL, 0, ftdi->usb_write_timeout) < 0)
            ftdi_error_return(-1, "unable to write eeprom");
    }

    return 0;
}

#define MAGIC 0x55aa
int ftdi_erase_eeprom(struct ftdi_context *ftdi)
{
    unsigned short eeprom_value;
    if (ftdi == NULL || ftdi->usb_dev == NULL)
        ftdi_error_return(-2, "USB device unavailable");

    if (ftdi->type == TYPE_R)
    {
        ftdi->eeprom->chip = 0;
        return 0;
    }

    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_ERASE_EEPROM_REQUEST,
                                0, 0, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "unable to erase eeprom");


    /* detect chip type by writing 0x55AA as magic at word position 0xc0
       Chip is 93x46 if magic is read at word position 0x00, as wraparound happens around 0x40
       Chip is 93x56 if magic is read at word position 0x40, as wraparound happens around 0x80
       Chip is 93x66 if magic is only read at word position 0xc0*/
    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE,
                                SIO_WRITE_EEPROM_REQUEST, MAGIC, 0xc0,
                                NULL, 0, ftdi->usb_write_timeout) != 0)
        ftdi_error_return(-3, "Writing magic failed");
    if (ftdi_read_eeprom_location( ftdi, 0x00, &eeprom_value))
        ftdi_error_return(-4, "Reading failed failed");
    if (eeprom_value == MAGIC)
    {
        ftdi->eeprom->chip = 0x46;
    }
    else
    {
        if (ftdi_read_eeprom_location( ftdi, 0x40, &eeprom_value))
            ftdi_error_return(-4, "Reading failed failed");
        if (eeprom_value == MAGIC)
            ftdi->eeprom->chip = 0x56;
        else
        {
            if (ftdi_read_eeprom_location( ftdi, 0xc0, &eeprom_value))
                ftdi_error_return(-4, "Reading failed failed");
            if (eeprom_value == MAGIC)
                ftdi->eeprom->chip = 0x66;
            else
            {
                ftdi->eeprom->chip = -1;
            }
        }
    }
    if (libusb_control_transfer(ftdi->usb_dev, FTDI_DEVICE_OUT_REQTYPE, SIO_ERASE_EEPROM_REQUEST,
                                0, 0, NULL, 0, ftdi->usb_write_timeout) < 0)
        ftdi_error_return(-1, "unable to erase eeprom");
    return 0;
}

char *ftdi_get_error_string (struct ftdi_context *ftdi)
{
    if (ftdi == NULL)
        return "";

    return ftdi->error_str;
}

/* @} end of doxygen libftdi group */