The DMIC DAI driver specifies a number of 1 to 8 channels for each DAI. The actual number of mics can currently not be configured in the device tree or audio glue, but is derived from the min/max channels of the CPU and codec DAI. A typical CPU DAI has two or more channels, in consequence a single mic is treated as a stereo/multi channel device, even though only one channel carries audio data.
This change adds the option to specify the number of used DMIC channels in the device tree. If a single channel is used we export a channel map that marks all unused channels as invalid to indicate userspace that the capture device is mono.
Signed-off-by: Matthias Kaehlcke mka@chromium.org --- Documentation/devicetree/bindings/sound/dmic.txt | 2 + sound/soc/codecs/dmic.c | 72 +++++++++++++++++++++--- 2 files changed, 65 insertions(+), 9 deletions(-)
diff --git a/Documentation/devicetree/bindings/sound/dmic.txt b/Documentation/devicetree/bindings/sound/dmic.txt index 54c8ef6498a8..f7bf65611453 100644 --- a/Documentation/devicetree/bindings/sound/dmic.txt +++ b/Documentation/devicetree/bindings/sound/dmic.txt @@ -7,10 +7,12 @@ Required properties:
Optional properties: - dmicen-gpios: GPIO specifier for dmic to control start and stop + - num-channels: Number of microphones on this DAI
Example node:
dmic_codec: dmic@0 { compatible = "dmic-codec"; dmicen-gpios = <&gpio4 3 GPIO_ACTIVE_HIGH>; + num-channels = <1>; }; diff --git a/sound/soc/codecs/dmic.c b/sound/soc/codecs/dmic.c index b88a1ee66f80..c705a25b138e 100644 --- a/sound/soc/codecs/dmic.c +++ b/sound/soc/codecs/dmic.c @@ -29,24 +29,29 @@ #include <sound/soc.h> #include <sound/soc-dapm.h>
+struct dmic { + struct gpio_desc *gpio_en; + int channels; +}; + 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 *dmic = snd_soc_dai_get_drvdata(dai);
- if (!dmic_en) + if (!dmic || !dmic->gpio_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); + gpiod_set_value(dmic->gpio_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); + gpiod_set_value(dmic->gpio_en, 0); break; }
@@ -57,6 +62,42 @@ static const struct snd_soc_dai_ops dmic_dai_ops = { .trigger = dmic_daiops_trigger, };
+const struct snd_pcm_chmap_elem dmic_chmaps_single[] = { + { .channels = 1, + .map = { SNDRV_CHMAP_MONO } }, + { .channels = 2, + .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_NA } }, + { .channels = 4, + .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_NA, + SNDRV_CHMAP_NA, SNDRV_CHMAP_NA } }, + { .channels = 6, + .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_NA, + SNDRV_CHMAP_NA, SNDRV_CHMAP_NA, + SNDRV_CHMAP_NA, SNDRV_CHMAP_NA } }, + { .channels = 8, + .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_NA, + SNDRV_CHMAP_NA, SNDRV_CHMAP_NA, + SNDRV_CHMAP_NA, SNDRV_CHMAP_NA, + SNDRV_CHMAP_NA, SNDRV_CHMAP_NA } }, + { } +}; + +static int dmic_pcm_new(struct snd_soc_pcm_runtime *rtd, + struct snd_soc_dai *dai) +{ + struct dmic *dmic = snd_soc_dai_get_drvdata(dai); + int err; + + if (dmic->channels == 1) { + err = snd_pcm_add_chmap_ctls(rtd->pcm, SNDRV_PCM_STREAM_CAPTURE, + dmic_chmaps_single, 8, 0, NULL); + if (err < 0) + return err; + } + + return 0; +} + static struct snd_soc_dai_driver dmic_dai = { .name = "dmic-hifi", .capture = { @@ -69,18 +110,31 @@ static struct snd_soc_dai_driver dmic_dai = { | SNDRV_PCM_FMTBIT_S16_LE, }, .ops = &dmic_dai_ops, + .pcm_new = dmic_pcm_new, };
static int dmic_codec_probe(struct snd_soc_codec *codec) { - struct gpio_desc *dmic_en; + struct dmic *dmic; + int err; + u32 pval; + + dmic = devm_kzalloc(codec->dev, sizeof(*dmic), GFP_KERNEL); + if (!dmic) + return -ENOMEM;
- dmic_en = devm_gpiod_get_optional(codec->dev, + dmic->gpio_en = devm_gpiod_get_optional(codec->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); + + err = of_property_read_u32(codec->dev->of_node, "num-channels", &pval); + if (!err) + dmic->channels = (int)pval; + else if (err != -ENOENT) + return err;
- snd_soc_codec_set_drvdata(codec, dmic_en); + snd_soc_codec_set_drvdata(codec, dmic);
return 0; }