2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 #include <linux/init.h>
19 #include <linux/usb.h>
25 * combine bytes and get an integer value
27 unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
30 case 1: return *bytes;
31 case 2: return combine_word(bytes);
32 case 3: return combine_triple(bytes);
33 case 4: return combine_quad(bytes);
39 * parse descriptor buffer and return the pointer starting the given
42 void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
54 if (p[1] == dtype && (!after || (void *)p > after)) {
63 * find a class-specified interface descriptor with the given subtype.
65 void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
67 unsigned char *p = after;
69 while ((p = snd_usb_find_desc(buffer, buflen, p,
70 USB_DT_CS_INTERFACE)) != NULL) {
71 if (p[0] >= 3 && p[2] == dsubtype)
78 * Wrapper for usb_control_msg().
79 * Allocates a temp buffer to prevent dmaing from/to the stack.
81 int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
82 __u8 requesttype, __u16 value, __u16 index, void *data,
83 __u16 size, int timeout)
89 buf = kmemdup(data, size, GFP_KERNEL);
93 err = usb_control_msg(dev, pipe, request, requesttype,
94 value, index, buf, size, timeout);
96 memcpy(data, buf, size);
102 unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
103 struct usb_host_interface *alts)
105 if (snd_usb_get_speed(chip->dev) == USB_SPEED_HIGH &&
106 get_endpoint(alts, 0)->bInterval >= 1 &&
107 get_endpoint(alts, 0)->bInterval <= 4)
108 return get_endpoint(alts, 0)->bInterval - 1;