summaryrefslogtreecommitdiffstats
path: root/sound/usb/helper.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-20 18:41:44 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-20 18:41:44 +0200
commit7f06a8b26aba1dc03b42272dc0089a800372c575 (patch)
tree7c67198f83d069eb13fd417e022d111b7e4c82a1 /sound/usb/helper.c
parentMerge branch 'for-linus/i2c-2635' of git://git.fluff.org/bjdooks/linux (diff)
parentMerge branch 'topic/asoc' into for-linus (diff)
downloadlinux-7f06a8b26aba1dc03b42272dc0089a800372c575.tar.xz
linux-7f06a8b26aba1dc03b42272dc0089a800372c575.zip
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6: (250 commits) ALSA: hda: Storage class should be before const qualifier ASoC: tpa6130a2: Remove CPVSS and HPVdd supplies ASoC: tpa6130a2: Define output pins with SND_SOC_DAPM_OUTPUT ASoC: sdp4430 - add sdp4430 pcm ops to DAI. ASoC: TWL6040: Enable earphone path in codec ASoC: SDP4430: Add support for Earphone speaker ASoC: SDP4430: Add sdp4430 machine driver ASoC: tlv320dac33: Avoid powering off while in BIAS_OFF ASoC: tlv320dac33: Use dev_dbg in dac33_hard_power function ALSA: sound/pci/asihpi: Use kzalloc ALSA: hdmi - dont fail on extra nodes ALSA: intelhdmi - add id for the CougarPoint chipset ALSA: intelhdmi - user friendly codec name ALSA: intelhdmi - add dependency on SND_DYNAMIC_MINORS ALSA: asihpi: incorrect range check ALSA: asihpi: testing the wrong variable ALSA: es1688: add pedantic range checks ARM: McBSP: Add support for omap4 in McBSP driver ARM: McBSP: Fix request for irq in OMAP4 OMAP: McBSP: Add 32-bit mode support ...
Diffstat (limited to 'sound/usb/helper.c')
-rw-r--r--sound/usb/helper.c113
1 files changed, 113 insertions, 0 deletions
diff --git a/sound/usb/helper.c b/sound/usb/helper.c
new file mode 100644
index 000000000000..d48d6f8f6ac9
--- /dev/null
+++ b/sound/usb/helper.c
@@ -0,0 +1,113 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include "usbaudio.h"
+#include "helper.h"
+
+/*
+ * combine bytes and get an integer value
+ */
+unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
+{
+ switch (size) {
+ case 1: return *bytes;
+ case 2: return combine_word(bytes);
+ case 3: return combine_triple(bytes);
+ case 4: return combine_quad(bytes);
+ default: return 0;
+ }
+}
+
+/*
+ * parse descriptor buffer and return the pointer starting the given
+ * descriptor type.
+ */
+void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
+{
+ u8 *p, *end, *next;
+
+ p = descstart;
+ end = p + desclen;
+ for (; p < end;) {
+ if (p[0] < 2)
+ return NULL;
+ next = p + p[0];
+ if (next > end)
+ return NULL;
+ if (p[1] == dtype && (!after || (void *)p > after)) {
+ return p;
+ }
+ p = next;
+ }
+ return NULL;
+}
+
+/*
+ * find a class-specified interface descriptor with the given subtype.
+ */
+void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
+{
+ unsigned char *p = after;
+
+ while ((p = snd_usb_find_desc(buffer, buflen, p,
+ USB_DT_CS_INTERFACE)) != NULL) {
+ if (p[0] >= 3 && p[2] == dsubtype)
+ return p;
+ }
+ return NULL;
+}
+
+/*
+ * Wrapper for usb_control_msg().
+ * Allocates a temp buffer to prevent dmaing from/to the stack.
+ */
+int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
+ __u8 requesttype, __u16 value, __u16 index, void *data,
+ __u16 size, int timeout)
+{
+ int err;
+ void *buf = NULL;
+
+ if (size > 0) {
+ buf = kmemdup(data, size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ }
+ err = usb_control_msg(dev, pipe, request, requesttype,
+ value, index, buf, size, timeout);
+ if (size > 0) {
+ memcpy(data, buf, size);
+ kfree(buf);
+ }
+ return err;
+}
+
+unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
+ struct usb_host_interface *alts)
+{
+ if (snd_usb_get_speed(chip->dev) == USB_SPEED_HIGH &&
+ get_endpoint(alts, 0)->bInterval >= 1 &&
+ get_endpoint(alts, 0)->bInterval <= 4)
+ return get_endpoint(alts, 0)->bInterval - 1;
+ else
+ return 0;
+}
+