linux-kernel - Re: [PATCH v2 1/2] ASoC: codec: use enable pin to control dmic start and stop

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Date:   Mon, 4 Sep 2017 12:03:21 +0200
From:   Arnaud Pouliquen <arnaud.pouliquen@...com>
To:     Lin Huang <hl@...k-chips.com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "dgreif@...omium.org" <dgreif@...omium.org>
CC:     "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "briannorris@...omium.org" <briannorris@...omium.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "tiwai@...e.com" <tiwai@...e.com>,
        "mka@...omium.org" <mka@...omium.org>,
        "dianders@...omium.org" <dianders@...omium.org>
Subject: Re: [PATCH v2 1/2] ASoC: codec: use enable pin to control dmic start
 and stop

Hello Lin,

Sorry for this late answer.
I'm not maintainer, just a contributor... but as some update seems
strange for me, so i prefer to highlight it to clarify them.

On 08/17/2017 04:24 AM, Lin Huang wrote:
> From: huang lin <hl@...k-chips.com>
> 
> on some board use enable pin to control dmic start and stop,
> so add this feature in dmic driver.
Please, Could you give data-sheet reference of your DMIC, to help me
to understand your use-case?
> 
> Signed-off-by: Lin Huang <hl@...k-chips.com>
> ---
>  sound/soc/codecs/Kconfig |  2 +-
>  sound/soc/codecs/dmic.c  | 46 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 47 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
> index 010811e..d98233b 100644
> --- a/sound/soc/codecs/Kconfig
> +++ b/sound/soc/codecs/Kconfig
> @@ -71,7 +71,7 @@ config SND_SOC_ALL_CODECS
>  	select SND_SOC_DA732X if I2C
>  	select SND_SOC_DA9055 if I2C
>  	select SND_SOC_DIO2125
> -	select SND_SOC_DMIC
> +	select SND_SOC_DMIC if GPIOLIB
Dependency also for DMIC without GPIO to handle gating?
>  	select SND_SOC_ES8316 if I2C
>  	select SND_SOC_ES8328_SPI if SPI_MASTER
>  	select SND_SOC_ES8328_I2C if I2C
> diff --git a/sound/soc/codecs/dmic.c b/sound/soc/codecs/dmic.c
> index 12e07f9..b88a1ee 100644
> --- a/sound/soc/codecs/dmic.c
> +++ b/sound/soc/codecs/dmic.c
> @@ -19,6 +19,8 @@
>   *
>   */
>  
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
>  #include <linux/module.h>
> @@ -27,6 +29,34 @@
>  #include <sound/soc.h>
>  #include <sound/soc-dapm.h>
>  
> +static int dmic_daiops_trigger(struct snd_pcm_substream *substream,
> +		int cmd, struct snd_soc_dai *dai)
> +{
> +	struct gpio_desc *dmic_en = snd_soc_dai_get_drvdata(dai);
> +
> +	if (!dmic_en)
> +		return 0;
> +
> +	switch (cmd) {
> +	case SNDRV_PCM_TRIGGER_START:
> +	case SNDRV_PCM_TRIGGER_RESUME:
> +	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +		gpiod_set_value(dmic_en, 1);
> +		break;
> +	case SNDRV_PCM_TRIGGER_STOP:
> +	case SNDRV_PCM_TRIGGER_SUSPEND:
> +	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
> +		gpiod_set_value(dmic_en, 0);
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct snd_soc_dai_ops dmic_dai_ops = {
> +	.trigger	= dmic_daiops_trigger,
> +};
> +
should it be handle by trigger or DAPM?



>  static struct snd_soc_dai_driver dmic_dai = {
>  	.name = "dmic-hifi",
>  	.capture = {
> @@ -38,8 +68,23 @@ static struct snd_soc_dai_driver dmic_dai = {
>  			| SNDRV_PCM_FMTBIT_S24_LE
>  			| SNDRV_PCM_FMTBIT_S16_LE,
>  	},
> +	.ops    = &dmic_dai_ops,
>  };
>  
> +static int dmic_codec_probe(struct snd_soc_codec *codec)
> +{
> +	struct gpio_desc *dmic_en;
> +
> +	dmic_en = devm_gpiod_get_optional(codec->dev,
> +					"dmicen", GPIOD_OUT_LOW);
Hypothesis here is that GPIO is always set to low? seems too limiting.

Regards
Arnaud
> +	if (IS_ERR(dmic_en))
> +		return PTR_ERR(dmic_en);
> +
> +	snd_soc_codec_set_drvdata(codec, dmic_en);
> +
> +	return 0;
> +}
> +
>  static const struct snd_soc_dapm_widget dmic_dapm_widgets[] = {
>  	SND_SOC_DAPM_AIF_OUT("DMIC AIF", "Capture", 0,
>  			     SND_SOC_NOPM, 0, 0),
> @@ -51,6 +96,7 @@ static const struct snd_soc_dapm_route intercon[] = {
>  };
>  
>  static const struct snd_soc_codec_driver soc_dmic = {
> +	.probe = dmic_codec_probe,
>  	.component_driver = {
>  		.dapm_widgets		= dmic_dapm_widgets,
>  		.num_dapm_widgets	= ARRAY_SIZE(dmic_dapm_widgets),
>