[2/2] ASoC: max98088: fix initial dai mute state

Commit Message

Rouven Czerwinski Dec. 13, 2022, 9:53 a.m. UTC

From: Marco Felsch <[e-mail]>

According the datasheets [1], [2] the initial value of register
0x2f/0x31 (dai1/dai2) is 0x00 which means that dai is unmuted. So upon
the first playback request the register is not touched since it is
cached by regmap. But the device output keeps silent. After ending the
playback session the mute() callback updates the register. Now the 2nd
playback request updates the register again (-> unmute the device) and
now we can really hear the output signal.

I've checked the register initial value which is '0x00' so the driver is
correct. Accroding the above inspections it seems that the hardware does
not update the register correctly on power up because the output is
muted.

To fix that we need to explicit set the mute state. Now the first
playback request gets played correctly.

[1] https://datasheets.maximintegrated.com/en/ds/MAX98089.pdf
[2] https://datasheets.maximintegrated.com/en/ds/MAX98088.pdf

Signed-off-by: Marco Felsch <[e-mail]>
---
 sound/soc/codecs/max98088.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Mark Brown Dec. 13, 2022, 12:01 p.m. UTC | #1

On Tue, Dec 13, 2022 at 10:53:28AM +0100, Rouven Czerwinski wrote:

> To fix that we need to explicit set the mute state. Now the first
> playback request gets played correctly.

> +++ b/sound/soc/codecs/max98088.c
> @@ -1710,6 +1710,11 @@ static int max98088_probe(struct snd_soc_component *component)
>         snd_soc_component_write(component, M98088_REG_1E_DAI2_IOCFG,
>                 M98088_S2NORMAL|M98088_SDATA);
>  
> +       snd_soc_component_update_bits(component, M98088_REG_2F_LVL_DAI1_PLAY,
> +               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
> +       snd_soc_component_update_bits(component, M98088_REG_31_LVL_DAI2_PLAY,
> +               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
> +

Won't this be broken again after suspend?  The device gets powered off
over suspend, then when it powers on again with the output unmuted
nothing will do another write since the register is already in the state
in the cache.

Marco Felsch Dec. 15, 2022, 9:17 a.m. UTC | #2

Hi Mark,

On 22-12-13, Mark Brown wrote:
> On Tue, Dec 13, 2022 at 10:53:28AM +0100, Rouven Czerwinski wrote:
> 
> > To fix that we need to explicit set the mute state. Now the first
> > playback request gets played correctly.
> 
> > +++ b/sound/soc/codecs/max98088.c
> > @@ -1710,6 +1710,11 @@ static int max98088_probe(struct snd_soc_component *component)
> >         snd_soc_component_write(component, M98088_REG_1E_DAI2_IOCFG,
> >                 M98088_S2NORMAL|M98088_SDATA);
> >  
> > +       snd_soc_component_update_bits(component, M98088_REG_2F_LVL_DAI1_PLAY,
> > +               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
> > +       snd_soc_component_update_bits(component, M98088_REG_31_LVL_DAI2_PLAY,
> > +               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
> > +
> 
> Won't this be broken again after suspend?  The device gets powered off
> over suspend, then when it powers on again with the output unmuted
> nothing will do another write since the register is already in the state
> in the cache.

I didn't found any suspend logic within the driver. Is this handled
within the ASoC core?

Regards,
  Marco

Mark Brown Dec. 15, 2022, noon UTC | #3

On Thu, Dec 15, 2022 at 10:17:47AM +0100, Marco Felsch wrote:
> On 22-12-13, Mark Brown wrote:

> > > +       snd_soc_component_update_bits(component, M98088_REG_2F_LVL_DAI1_PLAY,
> > > +               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
> > > +       snd_soc_component_update_bits(component, M98088_REG_31_LVL_DAI2_PLAY,
> > > +               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
> > > +

> > Won't this be broken again after suspend?  The device gets powered off
> > over suspend, then when it powers on again with the output unmuted
> > nothing will do another write since the register is already in the state
> > in the cache.

> I didn't found any suspend logic within the driver. Is this handled
> within the ASoC core?

Register save and restore for the device won't be.

Patch

diff --git a/sound/soc/codecs/max98088.c b/sound/soc/codecs/max98088.c
index 7f108e147355..c00d7726ac04 100644
--- a/sound/soc/codecs/max98088.c
+++ b/sound/soc/codecs/max98088.c
@@ -1710,6 +1710,11 @@  static int max98088_probe(struct snd_soc_component *component)
        snd_soc_component_write(component, M98088_REG_1E_DAI2_IOCFG,
                M98088_S2NORMAL|M98088_SDATA);
 
+       snd_soc_component_update_bits(component, M98088_REG_2F_LVL_DAI1_PLAY,
+               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
+       snd_soc_component_update_bits(component, M98088_REG_31_LVL_DAI2_PLAY,
+               M98088_DAI_MUTE_MASK, M98088_DAI_MUTE);
+
        max98088_handle_pdata(component);
 
 err_access: