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Commit 132fcb46 authored by Jassi Brar's avatar Jassi Brar Committed by Felipe Balbi
Browse files

usb: gadget: Add Audio Class 2.0 Driver 



This is a flexible USB Audio Class 2.0 compliant gadget driver that
implements a simple topology with a virtual sound card exposed at
the function side.

The driver doesn't expect any real audio codec to be present on the
function - the audio streams are simply sinked to and sourced from a
virtual ALSA sound card created. The user-space application may choose
to do whatever it wants with the data received from the USB Host and
choose to provide whatever it wants as audio data to the USB Host.

Capture(USB-Out) and Playback(USB-In) can be run at independent
configurations specified via module parameters while loading the driver.

Make this new version as the default selection by a new Kconfig choice.

Signed-off-by: default avatarYadi Brar <yadi.brar01@gmail.com>
Signed-off-by: default avatarJassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent d747a916

drivers/usb/gadget/Kconfig

+19 −6
Original line number Diff line number Diff line
@@ -599,16 +599,29 @@ config USB_AUDIO 
	depends on SND

	select SND_PCM

	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.

	  This Gadget Audio driver is compatible with USB Audio Class

	  specification 2.0. It implements 1 AudioControl interface,

	  1 AudioStreaming Interface each for USB-OUT and USB-IN.

	  Number of channels, sample rate and sample size can be

	  specified as module parameters.

	  This driver doesn't expect any real Audio codec to be present

	  on the device - the audio streams are simply sinked to and

	  sourced from a virtual ALSA sound card created. The user-space

	  application may choose to do whatever it wants with the data

	  received from the USB Host and choose to provide whatever it

	  wants as audio data to the USB Host.



	  Say "y" to link the driver statically, or "m" to build a

	  dynamically linked module called "g_audio".



config GADGET_UAC1

	bool "UAC 1.0 (Legacy)"

	depends on USB_AUDIO

	help

	  If you instead want older UAC Spec-1.0 driver that also has audio

	  paths hardwired to the Audio codec chip on-board and doesn't work

	  without one.



config USB_ETH

	tristate "Ethernet Gadget (with CDC Ethernet support)"

	depends on NET

drivers/usb/gadget/audio.c

+17 −3
Original line number Diff line number Diff line
@@ -14,10 +14,8 @@ 
#include <linux/kernel.h>

#include <linux/utsname.h>



#include "u_uac1.h"



#define DRIVER_DESC		"Linux USB Audio Gadget"

#define DRIVER_VERSION		"Dec 18, 2008"

#define DRIVER_VERSION		"Feb 2, 2012"



/*-------------------------------------------------------------------------*/
@@ -56,8 +54,13 @@ static struct usb_gadget_strings *audio_strings[] = { 
	NULL,

};



#ifdef CONFIG_GADGET_UAC1

#include "u_uac1.h"

#include "u_uac1.c"

#include "f_uac1.c"

#else

#include "f_uac2.c"

#endif



/*-------------------------------------------------------------------------*/
@@ -77,9 +80,15 @@ static struct usb_device_descriptor device_desc = { 


	.bcdUSB =		__constant_cpu_to_le16(0x200),



#ifdef CONFIG_GADGET_UAC1

	.bDeviceClass =		USB_CLASS_PER_INTERFACE,

	.bDeviceSubClass =	0,

	.bDeviceProtocol =	0,

#else

	.bDeviceClass =		USB_CLASS_MISC,

	.bDeviceSubClass =	0x02,

	.bDeviceProtocol =	0x01,

#endif

	/* .bMaxPacketSize0 = f(hardware) */



	/* Vendor and product id defaults change according to what configs
@@ -131,6 +140,9 @@ static struct usb_configuration audio_config_driver = { 
	.bConfigurationValue	= 1,

	/* .iConfiguration = DYNAMIC */

	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,

#ifndef CONFIG_GADGET_UAC1

	.unbind			= uac2_unbind_config,

#endif

};



/*-------------------------------------------------------------------------*/
@@ -180,7 +192,9 @@ static int __init audio_bind(struct usb_composite_dev *cdev) 


static int __exit audio_unbind(struct usb_composite_dev *cdev)

{

#ifdef CONFIG_GADGET_UAC1

	gaudio_cleanup();

#endif

	return 0;

}

drivers/usb/gadget/f_uac2.c

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