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 <m...@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;
}
--
2.16.0.rc0.223.g4a4ac83678-goog
