[alsa-devel] [PATCH 1/2] ASoC: wm8960: correct the min gain value of some PGA

[Charles Keepax]

On Thu, Sep 10, 2015 at 09:15:32AM +0800, Zidan Wang wrote:
> On Wed, Sep 09, 2015 at 12:49:54PM +0100, Charles Keepax wrote:
> > On Wed, Sep 09, 2015 at 07:29:10PM +0800, Zidan Wang wrote:
> > > The min gain is the corresponding gain value when the register value is 0
> > > instead of 1, just correct it.
> > > 
> > > Signed-off-by: Zidan Wang <zidan.wang at freescale.com>
> > > ---
> > >  sound/soc/codecs/wm8960.c | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/sound/soc/codecs/wm8960.c b/sound/soc/codecs/wm8960.c
> > > index e3b7d0c..6163474 100644
> > > --- a/sound/soc/codecs/wm8960.c
> > > +++ b/sound/soc/codecs/wm8960.c
> > > @@ -211,11 +211,11 @@ static int wm8960_put_deemph(struct snd_kcontrol *kcontrol,
> > >  	return wm8960_set_deemph(codec);
> > >  }
> > >  
> > > -static const DECLARE_TLV_DB_SCALE(adc_tlv, -9700, 50, 0);
> > > -static const DECLARE_TLV_DB_SCALE(dac_tlv, -12700, 50, 1);
> > > +static const DECLARE_TLV_DB_SCALE(adc_tlv, -9750, 50, 1);
> > > +static const DECLARE_TLV_DB_SCALE(dac_tlv, -12750, 50, 1);
> > 
> > The value zero is used for digital mute here. So I don't think it
> > is really appropriate to extend the TLV to show it as -97.5dB or
> > -127.5dB.
> 
> I think the min register value will corresponding to the min gain.
> So value 0 will also have a gain value, although it's for digital mute.
> 
> Refer to wm8962 codec driver, beep gain range is -90db~-6db, step in 6db,
> but it define the beep gain like below:
> static const DECLARE_TLV_DB_SCALE(beep_tlv, -9600, 600, 1);
> 

I might have to defer to Mark on this one then, if it is normal
to just use an additional gain value for mute in this type of
situation then it is ok with me. But it doesn't seem like that
would be a sensible thing, as you are asking for -97.5dB but
that is not what you are getting which doesn't seem like the
nicest interface.

Thanks,
Charles