[Gta04-owner] Another few milliamps.

[NeilBrown]

I recently turned the volume on my gta04 way up so that the alarm sound would
be clearly audible from the other room.
I was subsequently surprised to notice that there was a faint white-noise hum
coming from it while it was suspended.

It seems that the audio codec is not being turned off - either when not in
use, or in suspend.

I confirmed this with printks in twl4030_codec_enable() in
sound/soc/codecs/twl4030.c.

I hacked that function to always disable - never enable - and measured the
suspend current.  It had dropped from about 46mA to about 42mA.

So it seems we are wasting a few milliamps by leaving the codec on.

The code looks correct: twl4030_soc_suspend() calls
twl4030_set_bias_level(SND_SOC_BIAS_OFF), and that calls
twl4030_codec_enable(0), which will power off the codec.

But some how some part of that isn't happening.

I won't have time to look more deeply into this for a while, but if someone
has time and wants to hunt around in the code - insert lots of printks and
figure out why the codec isn't being turned off, I'm sure it would be a lot
of fun.

(this is in 3.2-gta04)

NeilBrown
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