USB: gadget: add USB Audio Gadget driver

Funtions added:
 - setup all the USB audio class device descriptors
 - handle class specific setup request
 - receive data from USB host by ISO transfer
 - play audio data by ALSA sound card
 - open and setup playback PCM interface
 - set default playback PCM parameters
 - provide playback functions for USB audio driver
 - provide PCM parameters set/get functions

Test on:
 - Host: Ubuntu 8.10, kernel 2.6.27
 - Gadget: EZKIT-BF548 with ASoC AD1980 codec

Todo:
 - add real Mute control code
 - add real Volume control code
 - maybe find another way to replace dynamic buffer handling
   with static buffer allocation
 - test on Windows system
 - provide control interface to handle mute/volume control
 - provide capture interface in the future
 - test on BF527, other USB device controler and other audio codec

Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 56 insertions, 0 deletions

diff --git a/drivers/usb/gadget/u_audio.h b/drivers/usb/gadget/u_audio.h
new file mode 100644
index 00000000000..cc8d159c648
--- /dev/null
+++ b/drivers/usb/gadget/u_audio.h
@@ -0,0 +1,56 @@
+/*
+ * u_audio.h -- interface to USB gadget "ALSA AUDIO" utilities
+ *
+ * Copyright (C) 2008 Bryan Wu <cooloney@kernel.org>
+ * Copyright (C) 2008 Analog Devices, Inc
+ *
+ * Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef __U_AUDIO_H
+#define __U_AUDIO_H
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/composite.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include "gadget_chips.h"
+
+/*
+ * This represents the USB side of an audio card device, managed by a USB
+ * function which provides control and stream interfaces.
+ */
+
+struct gaudio_snd_dev {
+        struct gaudio                   *card;
+        struct file                     *filp;
+        struct snd_pcm_substream        *substream;
+        int                             access;
+        int                             format;
+        int                             channels;
+        int                             rate;
+};
+
+struct gaudio {
+        struct usb_function             func;
+        struct usb_gadget               *gadget;
+
+        /* ALSA sound device interfaces */
+        struct gaudio_snd_dev           control;
+        struct gaudio_snd_dev           playback;
+        struct gaudio_snd_dev           capture;
+
+        /* TODO */
+};
+
+int gaudio_setup(struct gaudio *card);
+void gaudio_cleanup(struct gaudio *card);
+
+#endif /* __U_AUDIO_H */