[alsa-devel] [PATCH 7/8] ASoC: codecs: Add AB8500 codec-driver

Mark Brown broonie at opensource.wolfsonmicro.com
Fri Apr 27 13:11:24 CEST 2012

On Fri, Apr 27, 2012 at 12:54:59PM +0200, Ola Lilja wrote:
> On 04/27/2012 11:35 AM, Mark Brown wrote:

> > What are these regulators?  Are they internal PGA supplies or are they
> > microphone biases?

> These are mic-biases.

OK, then why aren't they hooked up in the board anyway (probably fixed to
a specific configuration there, though there are some use cases for
changing)?  This is what other CODEC drivers do with their MICBIASes...

> > Normally the clocking control is under the control of the machine driver
> > and if the machine driver wants to offer any options to userspace it'd
> > provide its own control - usually there's way more stuff going on here
> > than just selecting a source and much more coordination needed with the
> > drivers involved.

> Yes, we are only selecting what clock to request to the clock-driver-code, which
> then does its magic and taking decisions related to the whole platform.
> More specifically, in my context (that is audio) we will act upon being in
> voicecall or not, and in these cases requesting these two different clocks. By
> design this request comes from audio-code in userspace down to the audio-driver
> in the kernel. The clock-code will then turn of the clock not needed by us
> (audio) or any other party.

So what one would expect there would be that the machine driver would
figure things out - usually for something like the voice call case the
machine driver would be doing something like switching to the voice call
clock when the baseband DAI comes up.
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