[alsa-devel] Help with wm8731 support for the Utilite (imx6q)

[Jonathan Bennett]

With those changes:
[    8.656319] wm8731 2-001a: simple-card: set_sysclk error
[    8.661964] asoc-simple-card sound: ASoC: failed to init
202c000.ssi-wm8731-hifi: -22
[    8.670067] asoc-simple-card sound: ASoC: failed to instantiate card -22
[    8.678063] Bluetooth: vendor=0x2df, device=0x911b, class=255, fn=3
[    8.679996] asoc-simple-card: probe of sound failed with error -22


Looking at the 3.10 driver file and digging through some documentation, it
looks like the wm8731 can be used in either slave or master mode. According
to Compulab's driver, the supplying clocks when the wm8731 is in slave mode
are pll4 (IMX6QDL_CLK_PLL4_AUDIO) and ssi.1 (IMX6QDL_CLK_SSI2)

In master mode, it's IMX6QDL_CLK_CKO and IMX6QDL_CLK_CKO2.

I have not found an actual schematic to see how it is physically wired.
Popped open the case, and the codec is on the bottom side of the board with
the cpu on it, 100% unaccessible during operations. Even at that, the cpu
and codec are bga, so no probing of pins.

Looking at their driver file, I am also wondering if we need to tweak the
audmux init. I've played with this some in the dts, but hasn't made much
difference.

On Mon, Oct 20, 2014 at 11:29 AM, Fabio Estevam <festevam at gmail.com> wrote:

> On Mon, Oct 20, 2014 at 10:06 AM, Fabio Estevam <festevam at gmail.com>
> wrote:
>
> >>       clocks = <&clks IMX6QDL_CLK_SSI2>;
> >
> > This 'clocks' entry does not seem correct.
> >
> > IMX6QDL_CLK_SSI2 is the clock from SSI2 module, which is turned on by
> > the ssi driver.
> >
> > Who provides the MCLK for wm8731 on utilite board? Isn't it mx6 CLKO pin?
> >
> > Are you able to monitor this clock with a scope and make sure that it
> > is actually being turned on?
> >
> > We use CLKO output to drive MCLK pins on mx6qdl-sabresd board with
> > wm8762 codec. You can use it as a reference.
> >
> > Adding the Compulab's folks on Cc.
>
> Do the changes below help? (using IMX6QDL_CLK_CKO)
>
>     codec: wm8731 at 1a {
>        #sound-dai-cells = <0>;
>        compatible = "wlf,wm8731";
>        reg = <0x1a>;
>        AVDD-supply = <&reg_3p3v>;
>        HPVDD-supply = <&reg_3p3v>;
>        DCVDD-supply = <&reg_3p3v>;
>        DBVDD-supply = <&reg_3p3v>;
>        clocks = <&clks IMX6QDL_CLK_CKO>;
>
> with this one applied:
>
> --- a/sound/soc/codecs/wm8731.c
> +++ b/sound/soc/codecs/wm8731.c
> @@ -13,6 +13,7 @@
>   * published by the Free Software Foundation.
>   */
>
> +#include <linux/clk.h>
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/init.h>
> @@ -46,6 +47,7 @@ struct wm8731_priv {
>      struct regmap *regmap;
>      struct regulator_bulk_data supplies[WM8731_NUM_SUPPLIES];
>      const struct snd_pcm_hw_constraint_list *constraints;
> +    struct clk *mclk;
>      unsigned int sysclk;
>      int sysclk_type;
>      int playback_fs;
> @@ -742,6 +744,21 @@ static int wm8731_i2c_probe(struct i2c_client *i2c,
>          return ret;
>      }
>
> +    wm8731->mclk = devm_clk_get(&i2c->dev, NULL);
> +    if (IS_ERR(wm8731->mclk)) {
> +        ret = PTR_ERR(wm8731->mclk);
> +        dev_err(&i2c->dev, "Failed to get mclock: %d\n", ret);
> +        /* Defer the probe to see if the clk will be provided later */
> +        if (ret == -ENOENT)
> +            return -EPROBE_DEFER;
> +    }
> +
> +    if (!IS_ERR(wm8731->mclk)) {
> +        ret = clk_prepare_enable(wm8731->mclk);
> +        if (ret)
> +            return ret;
> +    }
> +
>      i2c_set_clientdata(i2c, wm8731);
>
>      ret = snd_soc_register_codec(&i2c->dev,
>