Unverified Commit 05c9b302 authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by Mark Brown
Browse files

ASoC: dmic: Add optional wakeup delay 



On some systems a delay is needed after switching on the clocks, to allow
the output to stabilize and avoid a popping noise at the beginning of
the recording. Add the optional device tree property 'wakeup-delay-ms'
and apply the specified delay after enabling the mic. A blocking delay
can't be applied in dmic_daiops_trigger() since the function is called
in atomic context. Instead use a DAPM event handler to set the enable
GPIO and apply the delay in the handler.

Signed-off-by: default avatarMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: default avatarPeter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 6d6c3946

Documentation/devicetree/bindings/sound/dmic.txt

+2 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ Required properties: 
Optional properties:

	- dmicen-gpios: GPIO specifier for dmic to control start and stop

	- num-channels: Number of microphones on this DAI

	- wakeup-delay-ms: Delay (in ms) after enabling the DMIC



Example node:
@@ -15,4 +16,5 @@ Example node: 
		compatible = "dmic-codec";

		dmicen-gpios = <&gpio4 3 GPIO_ACTIVE_HIGH>;

		num-channels = <1>;

		wakeup-delay-ms <50>;

	};

sound/soc/codecs/dmic.c

+35 −28
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
 *

 */



#include <linux/delay.h>

#include <linux/gpio.h>

#include <linux/gpio/consumer.h>

#include <linux/platform_device.h>
@@ -29,34 +30,33 @@ 
#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);

struct dmic {

	struct gpio_desc *gpio_en;

	int wakeup_delay;

};



	if (!dmic_en)

		return 0;

static int dmic_aif_event(struct snd_soc_dapm_widget *w,

			  struct snd_kcontrol *kcontrol, int event) {

	struct snd_soc_codec *codec = snd_soc_dapm_to_codec(w->dapm);

	struct dmic *dmic = snd_soc_codec_get_drvdata(codec);



	switch (cmd) {

	case SNDRV_PCM_TRIGGER_START:

	case SNDRV_PCM_TRIGGER_RESUME:

	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:

		gpiod_set_value(dmic_en, 1);

	switch (event) {

	case SND_SOC_DAPM_POST_PMU:

		if (dmic->gpio_en)

			gpiod_set_value(dmic->gpio_en, 1);



		if (dmic->wakeup_delay)

			msleep(dmic->wakeup_delay);

		break;

	case SNDRV_PCM_TRIGGER_STOP:

	case SNDRV_PCM_TRIGGER_SUSPEND:

	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:

		gpiod_set_value(dmic_en, 0);

	case SND_SOC_DAPM_POST_PMD:

		if (dmic->gpio_en)

			gpiod_set_value(dmic->gpio_en, 0);

		break;

	}



	return 0;

}



static const struct snd_soc_dai_ops dmic_dai_ops = {

	.trigger	= dmic_daiops_trigger,

};



static struct snd_soc_dai_driver dmic_dai = {

	.name = "dmic-hifi",

	.capture = {
@@ -68,26 +68,33 @@ 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_component_probe(struct snd_soc_component *component)

{

	struct gpio_desc *dmic_en;

	struct dmic *dmic;



	dmic = devm_kzalloc(component->dev, sizeof(*dmic), GFP_KERNEL);

	if (!dmic)

		return -ENOMEM;



	dmic_en = devm_gpiod_get_optional(component->dev,

	dmic->gpio_en = devm_gpiod_get_optional(component->dev,

						"dmicen", GPIOD_OUT_LOW);

	if (IS_ERR(dmic_en))

		return PTR_ERR(dmic_en);

	if (IS_ERR(dmic->gpio_en))

		return PTR_ERR(dmic->gpio_en);



	device_property_read_u32(component->dev, "wakeup-delay-ms",

				 &dmic->wakeup_delay);



	snd_soc_component_set_drvdata(component, dmic_en);

	snd_soc_component_set_drvdata(component, dmic);



	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),

	SND_SOC_DAPM_AIF_OUT_E("DMIC AIF", "Capture", 0,

			       SND_SOC_NOPM, 0, 0, dmic_aif_event,

			       SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD),

	SND_SOC_DAPM_INPUT("DMic"),

};

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