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@users.sourceforge.net>
Author.
COPYRIGHT¶
