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

[Mark Brown]

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.

> 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...