On 2018-02-16 19:53, Matthias Kaehlcke wrote:
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
Changes in v3:
- rebased on latest dmic topic branch
Changes in v2:
- use DAPM event handler instead of _prepare() and get rid of _trigger()
- skip error check for optional 'wakeup-delay-ms' property
- updated commit message
.../devicetree/bindings/sound/dmic.txt | 2 + sound/soc/codecs/dmic.c | 63 ++++++++++--------- 2 files changed, 37 insertions(+), 28 deletions(-)
diff --git a/Documentation/devicetree/bindings/sound/dmic.txt b/Documentation/devicetree/bindings/sound/dmic.txt index f7bf65611453..e957b4136716 100644 --- a/Documentation/devicetree/bindings/sound/dmic.txt +++ b/Documentation/devicetree/bindings/sound/dmic.txt @@ -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>;diff --git a/sound/soc/codecs/dmic.c b/sound/soc/codecs/dmic.c index 32a8f71d51f1..bac5bbb2dd59 100644 --- a/sound/soc/codecs/dmic.c +++ b/sound/soc/codecs/dmic.c @@ -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);
- 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->gpio_en = devm_gpiod_get_optional(component->dev,
"dmicen", GPIOD_OUT_LOW);- if (IS_ERR(dmic->gpio_en))
return PTR_ERR(dmic->gpio_en);
- dmic_en = devm_gpiod_get_optional(component->dev,
"dmicen", GPIOD_OUT_LOW);- if (IS_ERR(dmic_en))
return PTR_ERR(dmic_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),};
- Péter
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