Allocate an unused string id
int usb_string_id(struct usb_composite_dev * cdev);
cdev
the device whose string descriptor IDs are being allocated
single threaded during gadget setup
usb_string_id() is called from bind callbacks to allocate string IDs. Drivers for functions, configurations, or gadgets will then store that ID in the appropriate descriptors and string table.
All string identifier should be allocated using this, usb_string_ids_tab() or usb_string_ids_n() routine, to ensure that for example different functions don't wrongly assign different meanings to the same identifier.
David Brownell <[email protected]>
Author.