Writing a driver for Sound Card

Writing a driver for Sound Card

[Ramya Desai]

Dear All,

I am new to this Linux Sound driver architecture (ALSA). I developed a
few drivers in Linux kernel environment for PCI based devices which
are of type character and block. I am going through the following link
for writing a driver for my custom sound card.

http://www.kernel.org/pub/linux/kernel/people/tiwai/docs/writing-an-alsa-driver.pdf

I have a doubt about the Linux sound driver architecture. I need to
develop the driver with mixer, player, recorder, MIDI etc. components.
Do I need to develop these components in single driver OR Do I need to
develop as a individual component (one driver for one component).

I looked into the /usr/src/linux-2.6.35/sound directory. I did not
understand it completely. Is there any driver (sample) which I can go
through?

Please let me know.

Any help greatly appreciated and helpful to me.

Thanks and Regards,
Srinivas G

Writing a driver for Sound Card

[Ramya Desai]

Dear All,

I am new to this Advanced Linux Sound Architecture (ALSA) driver. I developed a
few drivers in Linux kernel environment for PCI based devices which
are of type character and block. I am going through the following link
for writing a driver for my custom sound card.

http://www.kernel.org/pub/linux/kernel/people/tiwai/docs/writing-an-alsa-driver.pdf

I have a doubt about the Linux sound driver architecture. I need to
develop the driver with mixer, player, recorder, MIDI etc. components.
Do I need to develop these components in single driver OR Do I need to
develop as a individual component (one driver for one component).

I looked into the /usr/src/linux-2.6.35/sound directory. I did not
understand it completely. Is there any driver (sample) which I can go
through?

Please let me know.

Any help greatly appreciated and helpful to me.

Thanks and Regards,
Srinivas G

Re: Writing a driver for Sound Card

[Clemens Ladisch]

Ramya Desai wrote:
> I have a doubt about the Linux sound driver architecture. I need to
> develop the driver with mixer, player, recorder, MIDI etc. components.
> Do I need to develop these components in single driver OR Do I need to
> develop as a individual component (one driver for one component).

You can do this however you want; ALSA doesn't impose any restriction.

Many drivers choose put the code for different components in separate
source files because the components are actually independent.

When a driver uses other modules, this is usually because that hardware
is common for multiple sound cards (e.g., most MIDI interfaces are
compatible with the Roland MPU-401).

> I looked into the /usr/src/linux-2.6.35/sound directory. I did not
> understand it completely. Is there any driver (sample) which I can go
> through?

The basic driver structure is explained in the documentation; most of
the additional code in drivers handles the quirks of actual hardware
and would not be very helpful for you.  Do you have any specific
questions?

Please tell us more about the architecture of your hardware.


Regards,
Clemens

Re: Writing a driver for Sound Card

[@ 2010-11-23 23:27 UTC (permalink / raw)]

On 11/23/2010 01:21 PM, Ramya Desai wrote:
> Dear All,
> 
> I am new to this Linux Sound driver architecture (ALSA). I developed a
> few drivers in Linux kernel environment for PCI based devices which
> are of type character and block. I am going through the following link
> for writing a driver for my custom sound card.

your best bet might be to subscribe to the either linux audio
developers' mailing list or the alsa-devel list and re-post your
question there. this list tends to be mainly for maintenance and the
occasional trading of patches.

good luck with your project,

jörn