[alsa-devel] [PATCH] ASoC: Intel: cht_bsw_rt5645: Add quirk for boards using pmc_plt_clk_0

[Sam McNally]

On Tue, 17 Sep 2019 at 01:02, Pierre-Louis Bossart
<pierre-louis.bossart at linux.intel.com> wrote:
>
> On 9/16/19 2:15 AM, Sam McNally wrote:
> > As of commit 648e921888ad ("clk: x86: Stop marking clocks as
> > CLK_IS_CRITICAL"), the cht_bsw_rt5645 driver needs to enable the clock
> > it's using for the codec's mclk. It does this from commit 7735bce05a9c
> > ("ASoC: Intel: boards: use devm_clk_get() unconditionally"), enabling
> > pmc_plt_clk_3. However, Strago family Chromebooks use pmc_plt_clk_0 for
> > the codec mclk, resulting in white noise with some digital microphones.
> > Add a DMI-based quirk for Strago family Chromebooks to use pmc_plt_clk_0
> > instead.
>
> Sounds good, thanks for the patch. You will need to Cc: maintainers
> (Takashi and Mark) if you want them to see your patches.
>
> Maybe you should mention in the commit message that this mirrors the
> changes made in cht_bsw_max98090_ti?
>
Will do.

> Also see more important comment below
>
> >
> > Signed-off-by: Sam McNally <sammc at chromium.org>
> > ---
> >
> >   sound/soc/intel/boards/cht_bsw_rt5645.c | 26 +++++++++++++++++++------
> >   1 file changed, 20 insertions(+), 6 deletions(-)
> >
> > diff --git a/sound/soc/intel/boards/cht_bsw_rt5645.c b/sound/soc/intel/boards/cht_bsw_rt5645.c
> > index 8879c3be29d5..c68a5b85a4a0 100644
> > --- a/sound/soc/intel/boards/cht_bsw_rt5645.c
> > +++ b/sound/soc/intel/boards/cht_bsw_rt5645.c
> > @@ -48,6 +48,7 @@ struct cht_mc_private {
> >   #define CHT_RT5645_SSP2_AIF2     BIT(16) /* default is using AIF1  */
> >   #define CHT_RT5645_SSP0_AIF1     BIT(17)
> >   #define CHT_RT5645_SSP0_AIF2     BIT(18)
> > +#define CHT_RT5645_PMC_PLT_CLK_0 BIT(19)
> >
> >   static unsigned long cht_rt5645_quirk = 0;
> >
> > @@ -59,6 +60,8 @@ static void log_quirks(struct device *dev)
> >               dev_info(dev, "quirk SSP0_AIF1 enabled");
> >       if (cht_rt5645_quirk & CHT_RT5645_SSP0_AIF2)
> >               dev_info(dev, "quirk SSP0_AIF2 enabled");
> > +     if (cht_rt5645_quirk & CHT_RT5645_PMC_PLT_CLK_0)
> > +             dev_info(dev, "quirk PMC_PLT_CLK_0 enabled");
> >   }
> >
> >   static int platform_clock_control(struct snd_soc_dapm_widget *w,
> > @@ -226,15 +229,21 @@ static int cht_aif1_hw_params(struct snd_pcm_substream *substream,
> >       return 0;
> >   }
> >
> > -/* uncomment when we have a real quirk
> >   static int cht_rt5645_quirk_cb(const struct dmi_system_id *id)
> >   {
> >       cht_rt5645_quirk = (unsigned long)id->driver_data;
> >       return 1;
> >   }
> > -*/
> >
> >   static const struct dmi_system_id cht_rt5645_quirk_table[] = {
> > +     {
> > +             /* Strago family Chromebooks */
> > +             .callback = cht_rt5645_quirk_cb,
> > +             .matches = {
> > +                     DMI_MATCH(DMI_PRODUCT_FAMILY, "Intel_Strago"),
> > +             },
> > +             .driver_data = (void *)CHT_RT5645_PMC_PLT_CLK_0,
> > +     },
> >       {
> >       },
> >   };
> > @@ -526,6 +535,7 @@ static int snd_cht_mc_probe(struct platform_device *pdev)
> >       int dai_index = 0;
> >       int ret_val = 0;
> >       int i;
> > +     const char *mclk_name;
> >
> >       drv = devm_kzalloc(&pdev->dev, sizeof(*drv), GFP_KERNEL);
> >       if (!drv)
> > @@ -662,11 +672,15 @@ static int snd_cht_mc_probe(struct platform_device *pdev)
> >       if (ret_val)
> >               return ret_val;
> >
> > -     drv->mclk = devm_clk_get(&pdev->dev, "pmc_plt_clk_3");
> > +     if (cht_rt5645_quirk & CHT_RT5645_PMC_PLT_CLK_0)
> > +             mclk_name = "pmc_plt_clk_0";
> > +     else
> > +             mclk_name = "pmc_plt_clk_3";
>
> Aren't you missing a call to dmi_first_match() to change the default
> value of this cht_rt5645_quirk variable?
>
> The rest of the patch looks good but I don't see how the DMI info is
> actually used.
>

The existing dmi_check_system() call at
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/tree/sound/soc/intel/boards/cht_bsw_rt5645.c?h=for-5.4&id=fca11622d600228bec405456f41590155b3a3eca#n630
uses the quirks table, calling the previously-commented-out callback
to assign to the quirks global. I'll add a mention in the description.

> > +     drv->mclk = devm_clk_get(&pdev->dev, mclk_name);
> >       if (IS_ERR(drv->mclk)) {
> > -             dev_err(&pdev->dev,
> > -                     "Failed to get MCLK from pmc_plt_clk_3: %ld\n",
> > -                     PTR_ERR(drv->mclk));
> > +             dev_err(&pdev->dev, "Failed to get MCLK from %s: %ld\n",
> > +                     mclk_name, PTR_ERR(drv->mclk)); >               return PTR_ERR(drv->mclk);
> >       }
> >
> >
>