linux-kernel - Re: [PATCH v2 2/2] ASoC: cs42l51: Correct PGA Volume minimum value

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Message-ID: <20221128171622.GI105268@ediswmail.ad.cirrus.com>
Date:   Mon, 28 Nov 2022 17:16:22 +0000
From:   Charles Keepax <ckeepax@...nsource.cirrus.com>
To:     Guillermo Rodriguez Garcia <guille.rodriguez@...il.com>
CC:     <broonie@...nel.org>, <lgirdwood@...il.com>,
        <alsa-devel@...a-project.org>, <patches@...nsource.cirrus.com>,
        <james.schulman@...rus.com>, <david.rhodes@...rus.com>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] ASoC: cs42l51: Correct PGA Volume minimum value

On Mon, Nov 28, 2022 at 12:14:43PM +0100, Guillermo Rodriguez Garcia wrote:
> El lun, 28 nov 2022 a las 10:48, Charles Keepax
> (<ckeepax@...nsource.cirrus.com>) escribió:
> > On Sat, Nov 26, 2022 at 12:15:10PM +0100, Guillermo Rodriguez Garcia wrote:
> > > El vie, 25 nov 2022 a las 17:37, Charles Keepax
> > > (<ckeepax@...nsource.cirrus.com>) escribió:
> > > >
> > > > The table in the datasheet actually shows the volume values in the wrong
> > > > order, with the two -3dB values being reversed. This appears to have
> > > > caused the lower of the two values to be used in the driver when the
> > > > higher should have been, correct this mixup.
> > > >
> > > > Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
> > > > ---
> > > > @@ -143,7 +143,7 @@ static const struct snd_kcontrol_new cs42l51_snd_controls[] = {
> > > >                         0, 0xA0, 96, adc_att_tlv),
> > > >         SOC_DOUBLE_R_SX_TLV("PGA Volume",
> > > >                         CS42L51_ALC_PGA_CTL, CS42L51_ALC_PGB_CTL,
> > > > -                       0, 0x19, 30, pga_tlv),
> > > > +                       0, 0x1A, 30, pga_tlv),
> > >
> > > The original patch where this control was added [1] already used 0x1A,
> > > however this was later changed to 0x19 in [2]. Your patch now reverts
> > > that change. Does this mean [2] was incorrect? If that is the case,
> > > shouldn't the commit message for this patch mention that it fixes [2]
> > > ?
> > >
> > >  [1]: https://lore.kernel.org/all/20200918134317.22574-1-guille.rodriguez@gmail.com/
> > >  [2]: https://lore.kernel.org/all/20220602162119.3393857-7-ckeepax@opensource.cirrus.com/
> > >
> >
> > Hmm... good digging, I didn't realise it was me who broke that.
> > Apologies in that chain I went around and checked a bunch of SX
> > controls to make sure they matched the datasheets, but it seems
> > I got a bit confused by the weird ordering of the values in the
> > datasheet. Since you have hardware would you be able to check,
> > before we merge this revert? A simple check that writing 0 to the
> > control sets the register value to 0x1A and writing 30 sets the
> > register to 0x18 would suffice.
> 
> Just checked. The values are correct after applying the patch:
> 
> $ amixer cset name='PGA Volume' '0','0'
> $ i2cget -y -f  2 0x4A 0x0A
> 0x1a
> $ i2cget -y -f  2 0x4A 0x0B
> 0x1a
> $ amixer cset name='PGA Volume' '30','30'
> $ i2cget -y -f  2 0x4A 0x0A
> 0x18
> $ i2cget -y -f  2 0x4A 0x0B
> 0x18

Excellent thank you so much for your help on this. I will send a
new version of the patch with the fixes tag applied.

Thanks,
Charles