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

[Valentin Raevsky]

Hi Jonathan,

See my comments in line.

Moreover, I'd appreciate it if you could try the CompuLab 3.10.17 kernel 
on your board in order to rule out a hw problem.

Take the latest 3.10.17 source from here:
https://github.com/utilite-computer/linux-kernel
tag: v3.10.17-cm-fx6-1-beta1

Build  instructions:

# export LOADADDR=0x10008000
# make cm_fx6_defconfig
# make zImage modules -j8 CONFIG_DEBUG_SECTION_MISMATCH=y
# make imx6q-sbc-fx6m.dtb
# make imx6q-sbc-fx6.dtb

imx6q-sbc-fx6m.dtb - Utilite
imx6q-sbc-fx6.dtb  - Evaluation Board

Regards,
Valentin.

On 10/20/2014 10:59 PM, Jonathan Bennett wrote:
> 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)
These clocks are correct for slave mode.
>
> In master mode, it's IMX6QDL_CLK_CKO and IMX6QDL_CLK_CKO2.
These clocks are correct for master mode, but do not try make it work.
Master mode requires a hw change on the module.

>
> 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
> <mailto:festevam at gmail.com>> wrote:
>
>     On Mon, Oct 20, 2014 at 10:06 AM, Fabio Estevam <festevam at gmail.com
>     <mailto: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,
>
>