[alsa-devel] Linux USB audio driver - sample code / link / documentation
Dear All,
I did not find a document for writing a USB audio driver under Linux environment. Please let me know any sample driver / link / document which describes about the USB audio driver under Linux environment.
Thanks and Regards, Ramya.
On 11/25/2010 01:51 AM, Ramya Desai wrote:
I did not find a document for writing a USB audio driver under Linux environment. Please let me know any sample driver / link / document which describes about the USB audio driver under Linux environment.
As Clemens wrote, examining existing drivers in the kernel repository (under sound/usb) might help you most. Just have a look how they communicate with the hardware and how they set up the ALSA components inside the kernel.
Is there any documentation for the chip you're writing the driver for, about the USB protocol it uses etc? Are you sure it does not follow the USB audio class specifications? Posting the output of 'lsusb -v' might also help.
Daniel
On Fri, Nov 26, 2010 at 1:53 AM, Daniel Mack zonque@gmail.com wrote:
On 11/25/2010 01:51 AM, Ramya Desai wrote:
I did not find a document for writing a USB audio driver under Linux environment. Please let me know any sample driver / link / document which describes about the USB audio driver under Linux environment.
As Clemens wrote, examining existing drivers in the kernel repository (under sound/usb) might help you most. Just have a look how they communicate with the hardware and how they set up the ALSA components inside the kernel.
Thank you very much for your reply.
I have gone through the sound/usb/* sources. However, I have also gone through the sound/soc/* sources. There is a documentation about the SOC implementation like platform driver, machine driver etc. The documentation is available in Documentation/sound/alsa/soc. Is there any documentation, like soc, for USB implementation?
Thanks and Regards, Ramya.
Ramya Desai wrote:
I did not find a document for writing a USB audio driver under Linux environment. Please let me know any sample driver / link / document which describes about the USB audio driver under Linux environment.
The simplest sample driver is this one: http://www.alsa-project.org/~clemens/ua1a.patch
If your device were class compliant, it would be supported by the standard driver.
Regards, Clemens
On Fri, Nov 26, 2010 at 1:21 PM, Clemens Ladisch clemens@ladisch.de wrote:
Ramya Desai wrote:
I did not find a document for writing a USB audio driver under Linux environment. Please let me know any sample driver / link / document which describes about the USB audio driver under Linux environment.
The simplest sample driver is this one: http://www.alsa-project.org/~clemens/ua1a.patch
Thank you very much for your link.
However, the source is also available at sound/usb/misc/ua101.c. What is the difference between sound/usb/misc/ua101.c and your patch (in the above link)?
Thanks and Regards, Ramya.
Ramya Desai wrote:
On Fri, Nov 26, 2010 at 1:21 PM, Clemens Ladisch clemens@ladisch.de wrote:
The simplest sample driver is this one: http://www.alsa-project.org/~clemens/ua1a.patch
the source is also available at sound/usb/misc/ua101.c.
No, that is for a different device. The UA-101 requires synchronization between capture and playback stream; because of this, the UA-1A's driver is somewhat simpler.
And there is no ALSA USB audio documentation.
Regards, Clemens
On Fri, Nov 26, 2010 at 3:25 PM, Clemens Ladisch clemens@ladisch.de wrote:
Ramya Desai wrote:
On Fri, Nov 26, 2010 at 1:21 PM, Clemens Ladisch clemens@ladisch.de wrote:
The simplest sample driver is this one: http://www.alsa-project.org/~clemens/ua1a.patch
the source is also available at sound/usb/misc/ua101.c.
No, that is for a different device. The UA-101 requires synchronization between capture and playback stream; because of this, the UA-1A's driver is somewhat simpler.
And there is no ALSA USB audio documentation.
Thanks again, Clemens. I will post if I get any problem while developing the driver.
Thanks and Regards, Ramya.
participants (3)
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Clemens Ladisch -
Daniel Mack -
Ramya Desai