[alsa-devel] DAPM over two regmaps (and a mailbox)

[Maxime Ripard]

Hi,

On Mon, Sep 19, 2016 at 10:56:10PM +0800, Chen-Yu Tsai wrote:
> On Mon, Sep 19, 2016 at 7:34 PM, Maxime Ripard
> <maxime.ripard at free-electrons.com> wrote:
> > On Mon, Sep 19, 2016 at 12:12:47PM +0100, Mark Brown wrote:
> >> On Mon, Sep 19, 2016 at 12:54:19PM +0200, Maxime Ripard wrote:
> >>
> >> > That codec is mapped in memory, however, we have a bunch of DAPM
> >> > widgets that are mapped in a separate register space, that should
> >> > probably be exposed through a syscon (but isn't yet).
> >>
> >> Why not just represent those as a separate device?
> >
> > I don't know, this seems to be supplies to muxers, mixers, DACs, the
> > amplifier (and the amplifier volume too, even though that's not a
> > widget), and it looks really intertwinned, how would you separate
> > them?
> 
> I asked Mark the same question a while ago. I was looking at the A31s
> codec, which is kind of a cross between A31 and A23.

We're working on the A33, that has yet another setup from the A23..

> Mark recommended using aux devices. AFAIU the codec would just
> register the DAC and ADC widgets, the digital volume control, and
> whatever digital bits there are. The analog side would be done in a
> asoc component driver, which would register all the analog widgets
> and controls. You then tie them together at the card level.

Ok. How would that work? Can you setup routes between widgets defined
in different components?

> AFAIK the digital parts and analog parts are in different power
> domains, probably to keep audio bypass working in standby mode.

I don't think we have control over those power domains though, do we?

> As for the A31s, I only got as far as implementing the regmap using
> custom read/write callbacks, and part of the register definition.
> Unfortunately I saved my work with git stash, which I accidentally
> wiped out with git reflog expire...

I guess some lessons are meant to be learned the hard way :)

Thanks,
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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