USB_INTERFACE_ID(9)                   Kernel Mode Gadget API                  USB_INTERFACE_ID(9)



NAME
       usb_interface_id - allocate an unused interface ID

SYNOPSIS
       int usb_interface_id(struct usb_configuration * config, struct usb_function * function);

ARGUMENTS
       config
           configuration associated with the interface

       function
           function handling the interface

CONTEXT
       single threaded during gadget setup

DESCRIPTION
       usb_interface_id is called from usb_function.bind callbacks to allocate new interface IDs.
       The function driver will then store that ID in interface, association, CDC union, and
       other descriptors. It will also handle any control requests targeted at that interface,
       particularly changing its altsetting via set_alt. There may also be class-specific or
       vendor-specific requests to handle.

       All interface identifier should be allocated using this routine, to ensure that for
       example different functions don't wrongly assign different meanings to the same
       identifier. Note that since interface identifiers are configuration-specific, functions
       used in more than one configuration (or more than once in a given configuration) need
       multiple versions of the relevant descriptors.

       Returns the interface ID which was allocated; or -ENODEV if no more interface IDs can be
       allocated.

AUTHOR
       David Brownell <dbrownell AT users.net>
           Author.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                       USB_INTERFACE_ID(9)