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 --- 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 cf83c423394d..b5f60ac22ace 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); 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_codec_probe(struct snd_soc_codec *codec) { - struct gpio_desc *dmic_en; + struct dmic *dmic; + + dmic = devm_kzalloc(codec->dev, sizeof(*dmic), GFP_KERNEL); + if (!dmic) + return -ENOMEM; + + dmic->gpio_en = devm_gpiod_get_optional(codec->dev, + "dmicen", GPIOD_OUT_LOW); + if (IS_ERR(dmic->gpio_en)) + return PTR_ERR(dmic->gpio_en);
- dmic_en = devm_gpiod_get_optional(codec->dev, - "dmicen", GPIOD_OUT_LOW); - if (IS_ERR(dmic_en)) - return PTR_ERR(dmic_en); + device_property_read_u32(codec->dev, "wakeup-delay-ms", + &dmic->wakeup_delay);
- snd_soc_codec_set_drvdata(codec, dmic_en); + snd_soc_codec_set_drvdata(codec, 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"), };