[alsa-devel] ASOC v2 driver structure

Liam Girdwood liam.girdwood at wolfsonmicro.com
Mon Jan 28 14:06:10 CET 2008

On Sun, 2008-01-27 at 14:15 -0500, Jon Smirl wrote:
> On 1/27/08, Jon Smirl <jonsmirl at gmail.com> wrote:
> > I'm trying to write an asoc v2 driver for my powerpc based SOC
> > (mpc5200) hardware. We have two audio devices on the board, a WM8580
> > and a TAS5504.  How do you do this with asoc v2? The card is created
> > in snd_soc_machine_create(); there seems to be an assumption of a
> > single card per machine.

This was the initial assumption in v1. To be honest we were only
catering for single codec devices. In v2 we are allowing multiple cards
- struct machine is being refactored atm to make this more obvious.

> >
> > Or are you supposed to mix the different devices into a single pcm
> > driver? What would happen in pxa2xx-pcm.c if more than one of these
> > were defined?
> I guess I'm supposed to have multiple platform drivers - one per
> I2C/AC97/SSC channel?

You could do this or create two cards (machines). I've kept platform as
the DMA + all the interfaces (as some devices have more than one
interface in operation e.g. AC97 for HiFi and I2S/PCM for voice).


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