usb_gadget_get

usb_gadget_get_string
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Name

usb_gadget_get_string — fill out a string descriptor

Synopsis

`int usb_gadget_get_string (`	struct usb_gadget_strings * `table`,
	int `id`,
	u8 * `buf)`;

Arguments

table: of c strings encoded using UTF-8
id: string id, from low byte of wValue in get string descriptor
buf: at least 256 bytes, must be 16-bit aligned

Description

Finds the UTF-8 string matching the ID, and converts it into a string descriptor in utf16-le. Returns length of descriptor (always even) or negative errno

If your driver needs stings in multiple languages, you'll probably “switch (wIndex) { ... }” in your ep0 string descriptor logic, using this routine after choosing which set of UTF-8 strings to use. Note that US-ASCII is a strict subset of UTF-8; any string bytes with the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1 characters (which are also widely used in C strings).