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

[Mark Brown]

On Thu, Sep 10, 2015 at 09:24:20AM +0100, Charles Keepax wrote:
> On Thu, Sep 10, 2015 at 09:15:32AM +0800, Zidan Wang wrote:

> > > > +static const DECLARE_TLV_DB_SCALE(adc_tlv, -9750, 50, 1);
> > > > +static const DECLARE_TLV_DB_SCALE(dac_tlv, -12750, 50, 1);

> > 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.

The last value in the scale macro is a flag saying if the minimum value
is mute - if it's set to 1 userspace should know this is what's going
on.
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