usb_epnum_to_ep_desc

Name

usb_epnum_to_ep_desc --  get the endpoint object with a given endpoint number

Synopsis

struct usb_endpoint_descriptor * usb_epnum_to_ep_desc (struct usb_device * dev, unsigned epnum);

Arguments

dev

the device whose current configuration+altsettings is considered

epnum

the desired endpoint, masked with USB_DIR_IN as appropriate.

Description

This walks the device descriptor for the currently active configuration, and returns a pointer to the endpoint with that particular endpoint number, or null.

Note that interface descriptors are not required to list endpoint numbers in any standardized order, so that it would be wrong to assume that ep2in precedes either ep5in, ep2out, or even ep1out. This routine helps device drivers avoid such mistakes.