[alsa-devel] [RFC v2 PATCH] ASoC: wm8904: add CCF support

[Boris BREZILLON]

Hello Bo,

Le 25/03/2014 10:56, Bo Shen a écrit :
> Enable WM8904 to support common clock framework.
>    - Now it supports use SoC provided clock or external oscillator
>      as MCLK.
>
> Signed-off-by: Bo Shen <voice.shen at atmel.com>
> ---
>   Documentation/devicetree/bindings/sound/wm8904.txt | 48 ++++++++++++++++++++++
>   sound/soc/codecs/wm8904.c                          | 17 ++++++++
>   2 files changed, 65 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/sound/wm8904.txt
>
> diff --git a/Documentation/devicetree/bindings/sound/wm8904.txt b/Documentation/devicetree/bindings/sound/wm8904.txt
> new file mode 100644
> index 0000000..bcf4aa0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sound/wm8904.txt
> @@ -0,0 +1,48 @@
> +WM8904 audio CODEC
> +
> +This device supports I2C only.
> +
> +Required properties:
> +  - compatible: "wlf,wm8904"
> +  - reg: the I2C address of the device.
> +  - clocks and clock-names: reference to
> +    <Documentation/devicetree/bindings/clock/clock-bindings.txt>
> +
> +Pins on the device (for linking into audio routes):
> +
> +  * IN1L
> +  * IN1R
> +  * IN2L
> +  * IN2R
> +  * IN3L
> +  * IN3R
> +  * HPOUTL
> +  * HPOUTR
> +  * LINEOUTL
> +  * LINEOUTR
> +  * MICBIAS
> +
> +Examples:
> +
> +1. Using SoC provided clock as mclk:
> +codec: wm8904 at 1a {
> +	compatible = "wlf,wm8904";
> +	reg = <0x1a>;
> +	clocks = <&pck0>;
> +	clock-names = "mclk";
> +};


> +
> +2. Using external oscillator as mclk:
> +codec: wm8904 at 1a {
> +	compatible = "wlf,wm8904";
> +	reg = <0x1a>;
> +
> +	wm8904_osc {
> +		compatible = "fixed-clock";
> +		#clock-cells = <0>;
> +		#clock-frequency = <12000000>;
> +	}
> +
> +	clocks = <&wm8904_osc>;
> +	clock-names = "mclk";
> +};

I think there is a misunderstanding here (and it certainly comes from my
explanations during our last talk :)): both cases should be handled the same
way because an external oscillator is no more or less than an external clk
(we don't care how this clk is generated).

I suggested to put the osc node inside the wm8904 one but I thought you were
trying to represent the internal 12MHz clk generated when using the fll free
running mode.

> diff --git a/sound/soc/codecs/wm8904.c b/sound/soc/codecs/wm8904.c
> index 49c35c3..4db6a26 100644
> --- a/sound/soc/codecs/wm8904.c
> +++ b/sound/soc/codecs/wm8904.c
> @@ -11,6 +11,7 @@
>    * published by the Free Software Foundation.
>    */
>   
> +#include <linux/clk.h>
>   #include <linux/module.h>
>   #include <linux/moduleparam.h>
>   #include <linux/init.h>
> @@ -49,6 +50,7 @@ static const char *wm8904_supply_names[WM8904_NUM_SUPPLIES] = {
>   /* codec private data */
>   struct wm8904_priv {
>   	struct regmap *regmap;
> +	struct clk *mclk;
>   
>   	enum wm8904_type devtype;
>   
> @@ -1828,6 +1830,9 @@ static int wm8904_set_bias_level(struct snd_soc_codec *codec,
>   
>   	switch (level) {
>   	case SND_SOC_BIAS_ON:
> +		if (IS_ENABLED(CONFIG_COMMON_CLK))
> +			if (wm8904->mclk)
> +				clk_prepare_enable(wm8904->mclk);
>   		break;
>   
>   	case SND_SOC_BIAS_PREPARE:
> @@ -1894,6 +1899,9 @@ static int wm8904_set_bias_level(struct snd_soc_codec *codec,
>   
>   		regulator_bulk_disable(ARRAY_SIZE(wm8904->supplies),
>   				       wm8904->supplies);
> +		if (IS_ENABLED(CONFIG_COMMON_CLK))
> +			if (wm8904->mclk)
> +				clk_disable_unprepare(wm8904->mclk);
>   		break;
>   	}
>   	codec->dapm.bias_level = level;
> @@ -2139,6 +2147,15 @@ static int wm8904_i2c_probe(struct i2c_client *i2c,
>   		return ret;
>   	}
>   
> +	if (IS_ENABLED(CONFIG_COMMON_CLK)) {
> +		wm8904->mclk = devm_clk_get(&i2c->dev, "mclk");
> +		if (IS_ERR(wm8904->mclk)) {
> +			dev_err(&i2c->dev, "Failed to get MCLK\n");
> +			ret = PTR_ERR(wm8904->mclk);
> +			goto err_enable;
> +		}
> +	}
> +
>   	ret = regmap_read(wm8904->regmap, WM8904_SW_RESET_AND_ID, &val);
>   	if (ret < 0) {
>   		dev_err(&i2c->dev, "Failed to read ID register: %d\n", ret);