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ASoC: dmic: Add optional wakeup delay

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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: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Matthias Kaehlcke 2018-02-16 09:53:12 -08:00 committed by Mark Brown
parent 6d6c3946d8
commit 05c9b302ed
No known key found for this signature in database
GPG key ID: 24D68B725D5487D0
2 changed files with 37 additions and 28 deletions
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2
Documentation/devicetree/bindings/sound/dmic.txt
View file

@ -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>;
};

63
sound/soc/codecs/dmic.c
View file

@ -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_en = devm_gpiod_get_optional(component->dev,
"dmicen", GPIOD_OUT_LOW);
if (IS_ERR(dmic_en))
return PTR_ERR(dmic_en);
dmic = devm_kzalloc(component->dev, sizeof(*dmic), GFP_KERNEL);
if (!dmic)
return -ENOMEM;
snd_soc_component_set_drvdata(component, dmic_en);
dmic->gpio_en = devm_gpiod_get_optional(component->dev,
"dmicen", GPIOD_OUT_LOW);
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);
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"),
};