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

From: Arnaud Pouliquen
Date: Mon Sep 04 2017 - 06:03:54 EST


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@xxxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxx>
> ---
> 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),
>