[linux-2.6-block.git] / drivers / usb / gadget / usbstring.c

/*
 * Copyright (C) 2003 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/nls.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>


/**
 * usb_gadget_get_string - fill out a string descriptor 
 * @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
 *
 * 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).
 */
int
usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf)
{
	struct usb_string	*s;
	int			len;

	/* descriptor 0 has the language id */
	if (id == 0) {
		buf [0] = 4;
		buf [1] = USB_DT_STRING;
		buf [2] = (u8) table->language;
		buf [3] = (u8) (table->language >> 8);
		return 4;
	}
	for (s = table->strings; s && s->s; s++)
		if (s->id == id)
			break;

	/* unrecognized: stall. */
	if (!s || !s->s)
		return -EINVAL;

	/* string descriptors have length, tag, then UTF16-LE text */
	len = min ((size_t) 126, strlen (s->s));
	len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,
			(wchar_t *) &buf[2], 126);
	if (len < 0)
		return -EINVAL;
	buf [0] = (len + 1) * 2;
	buf [1] = USB_DT_STRING;
	return buf [0];
}
EXPORT_SYMBOL_GPL(usb_gadget_get_string);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Copyright (C) 2003 David Brownell
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU Lesser General Public License as published
	6	* by the Free Software Foundation; either version 2.1 of the License, or
	7	* (at your option) any later version.
	8	*/
	9
	10	#include <linux/errno.h>
	11	#include <linux/kernel.h>
a84d9e53	12	#include <linux/module.h>
1da177e4 LT	13	#include <linux/list.h>
	14	#include <linux/string.h>
	15	#include <linux/device.h>
	16	#include <linux/init.h>
86dc243c	17	#include <linux/nls.h>
1da177e4	18
5f848137	19	#include <linux/usb/ch9.h>
9454a57a	20	#include <linux/usb/gadget.h>
1da177e4	21
1da177e4 LT	22
	23	/**
	24	* usb_gadget_get_string - fill out a string descriptor
	25	* @table: of c strings encoded using UTF-8
	26	* @id: string id, from low byte of wValue in get string descriptor
86dc243c	27	* @buf: at least 256 bytes, must be 16-bit aligned
1da177e4 LT	28	*
	29	* Finds the UTF-8 string matching the ID, and converts it into a
	30	* string descriptor in utf16-le.
	31	* Returns length of descriptor (always even) or negative errno
	32	*
	33	* If your driver needs stings in multiple languages, you'll probably
	34	* "switch (wIndex) { ... }" in your ep0 string descriptor logic,
	35	* using this routine after choosing which set of UTF-8 strings to use.
	36	* Note that US-ASCII is a strict subset of UTF-8; any string bytes with
	37	* the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1
	38	* characters (which are also widely used in C strings).
	39	*/
	40	int
	41	usb_gadget_get_string (struct usb_gadget_strings table, int id, u8 buf)
	42	{
	43	struct usb_string *s;
	44	int len;
	45
	46	/* descriptor 0 has the language id */
	47	if (id == 0) {
	48	buf [0] = 4;
	49	buf [1] = USB_DT_STRING;
	50	buf [2] = (u8) table->language;
	51	buf [3] = (u8) (table->language >> 8);
	52	return 4;
	53	}
	54	for (s = table->strings; s && s->s; s++)
	55	if (s->id == id)
	56	break;
	57
	58	/* unrecognized: stall. */
	59	if (!s \|\| !s->s)
	60	return -EINVAL;
	61
	62	/* string descriptors have length, tag, then UTF16-LE text */
	63	len = min ((size_t) 126, strlen (s->s));
86dc243c AS	64	len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,
86dc243c AS	65	(wchar_t *) &buf[2], 126);
1da177e4 LT	66	if (len < 0)
	67	return -EINVAL;
	68	buf [0] = (len + 1) * 2;
	69	buf [1] = USB_DT_STRING;
	70	return buf [0];
	71	}
a84d9e53	72	EXPORT_SYMBOL_GPL(usb_gadget_get_string);