usb_ifnum_to_if(9)
NAME
usb_ifnum_to_if - get the interface object with a given interface
number
SYNOPSIS
struct usb_interface * usb_ifnum_to_if(const struct usb_device * dev,
unsigned ifnum);
ARGUMENTS
- dev
- the device whose current configuration is considered
- ifnum
- the desired interface
DESCRIPTION
This walks the device descriptor for the currently active configuration
and returns a pointer to the interface with that particular interface
number, or null.
Note that configuration descriptors are not required to assign
interface numbers sequentially, so that it would be incorrect to assume
that the first interface in that descriptor corresponds to interface
zero. This routine helps device drivers avoid such mistakes. However,
you should make sure that you do the right thing with any alternate
settings available for this interfaces.
Donīt call this function unless you are bound to one of the interfaces
on this device or you have locked the device!