[alsa-devel] [PATCH] ALSA: ASoc: Add regulator support to CS4270 codec driver

[Daniel Mack]

On Wed, Nov 25, 2009 at 03:38:04PM +0000, Mark Brown wrote:
> On Wed, Nov 25, 2009 at 04:20:52PM +0100, Daniel Mack wrote:
> 
> > Ok - which place would you suggest for it? Is there an ASoC callback I
> > can hook on to tell me when the whole codec isn't used anymore? I can
> > only see startup/shutdown, but I would need to my own snd_pc_substream
> > handling login in there. Other drivers do that in the probe/remove
> 
> set_bias_level().  If the device is idle then the bias will be held in
> STANDBY (or OFF in future).  If you are happy switching off the analogue
> supply separately to the others then turn that one on when in PREPARE or
> ON, and kill the others only in OFF.

Ok, will do and resend later. Thanks!

> > functions, but that won't suffice for my board as we want VA disabled
> > whenever possible.
> 
> Are the power savings really that great?  If the power saving really is
> that critical it seems like a low power focused part might be a more
> natural choice...

The VA suplpy domain not only powers the codec but a bunch of OPAMPs and
the like as well. And yes, for all these, the power saving is
significant.

Daniel