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, 14 insertions, 0 deletions

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 924bb7a..ef9d908 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -580,6 +580,20 @@ config USB_ZERO_HNPTEST
 	  the "B-Peripheral" role, that device will use HNP to let this
 	  one serve as the USB host instead (in the "B-Host" role).
 
+config USB_AUDIO
+	tristate "Audio Gadget (EXPERIMENTAL)"
+	depends on SND
+	help
+	  Gadget Audio is compatible with USB Audio Class specification 1.0.
+	  It will include at least one AudioControl interface, zero or more
+	  AudioStream interface and zero or more MIDIStream interface.
+
+	  Gadget Audio will use on-board ALSA (CONFIG_SND) audio card to
+	  playback or capture audio stream.
+
+	  Say "y" to link the driver statically, or "m" to build a
+	  dynamically linked module called "g_audio".
+
 config USB_ETH
 	tristate "Ethernet Gadget (with CDC Ethernet support)"
 	depends on NET