Hi, On Fri, Aug 19, 2011 at 04:52:14PM +0530, Jassi Brar wrote: > 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. > > Signed-off-by: Yadi Brar <yadi.brar01@xxxxxxxxx> > Signed-off-by: Jassi Brar <jassisinghbrar@xxxxxxxxx> > --- > > =========== > How To Test > =========== > USB_DEV$ insmod g_audio2.ko c_srate=64000 p_srate=48000 ; say > gadget: high speed config #1: UAC2 > > USB_DEV$ aplay -l > **** List of PLAYBACK Hardware Devices **** > card 0: uac2 [uac2], device 0: UAC2 PCM [UAC2 PCM] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > > USB_DEV$ arecord -l > **** List of CAPTURE Hardware Devices **** > card 0: uac2 [uac2], device 0: UAC2 PCM [UAC2 PCM] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > > USB_HOST$ aplay -l > **** List of PLAYBACK Hardware Devices **** > card 0: PCH [HDA Intel PCH], device 0: ALC665 Analog [ALC665 Analog] > Subdevices: 0/1 > Subdevice #0: subdevice #0 > card 1: Gadget [UAC2 Gadget], device 0: USB Audio [USB Audio] <<<<<< > Subdevices: 1/1 > Subdevice #0: subdevice #0 > > USB_HOST$ arecord -l > **** List of CAPTURE Hardware Devices **** > card 0: PCH [HDA Intel PCH], device 0: ALC665 Analog [ALC665 Analog] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > card 1: Gadget [UAC2 Gadget], device 0: USB Audio [USB Audio] <<<<<<< > Subdevices: 1/1 > Subdevice #0: subdevice #0 > > After this confirmation, you should be able to use it just like another > sound card in your system. That is, a new sound card should appear in the > sound preferences which you can select to route your default audio to and > from. > > ============ > Test Results > ============ > The driver has been tested for Half as well as Full Duplex at > Stereo, S16_LE at 44.1KHz, 48KHz and 64KHz. It should also > work for other configurations as well, except for different > sample-size(TODO). > > Obviously, much depends upon the underlying UDC driver. > > While testing with OMAP's implementation of Inventra HDRC, I observed > some noise for configurations for which the USB-OUT packet size chosen > by the Host is not a power of 2. USB-IN works just fine. > For ex, on both Beagle/Panda board, 48KHz USB-OUT has some noise while > 64KHz is smooth. Also, with full duplex, it occasioanally shows noise. > > Taking benefit of doubt, I assume this driver has unmasked some subtle > bug in the underlying UDC's ISOCH handling code ;) > Please feel free to find issue with this driver by testing it over > some other UDC. > > drivers/usb/gadget/Kconfig | 20 + > drivers/usb/gadget/Makefile | 2 + > drivers/usb/gadget/audio2.c | 155 +++++ > drivers/usb/gadget/f_audio2.c | 1448 +++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 1625 insertions(+), 0 deletions(-) > create mode 100644 drivers/usb/gadget/audio2.c > create mode 100644 drivers/usb/gadget/f_audio2.c > > diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig > index e35dfef..95c65d8 100644 > --- a/drivers/usb/gadget/Kconfig > +++ b/drivers/usb/gadget/Kconfig > @@ -599,6 +599,26 @@ 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_2 > + tristate "Audio Gadget Class 2.0 (EXPERIMENTAL)" > + depends on SND && EXPERIMENTAL > + select SND_PCM > + help > + 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_audio2". > + > config USB_AUDIO > tristate "Audio Gadget (EXPERIMENTAL)" > depends on SND > diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile > index 7409338..fa8472e 100644 > --- a/drivers/usb/gadget/Makefile > +++ b/drivers/usb/gadget/Makefile > @@ -40,6 +40,7 @@ obj-$(CONFIG_USB_COMPOSITE) += usb-composite.o > # > g_zero-y := zero.o > g_audio-y := audio.o > +g_audio2-y := audio2.o instead of adding a new gadget driver, can't you just re-use g_audio and add what's missing ? -- balbi
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