The snd_pcm_hw_constraint_minmax() works fine when a single codec is connected to a single CPU DAI, but in multicodec or DPCM setup the constraints placed by the driver will apply to the whole PCM stream (FE included) and thus prevents more than 8 playback channels for example.

Signed-off-by: Peter Ujfalusi peter.ujfalusi@ti.com --- Hi,

I have a board which uses two pcm3168a codec connected to one McASP port with parallel serializers. One 16 channel (2x 8 channel) playback and one 12 (2x 6 channel) capture should be possible as I use only one CPU DAI + platform. However no matter how I tried to set things up ALSA blocked more than 8 channel playback in simple multicodec or DPCM setup.

It turned out that the constraint set by the codec on the BE is actually applies to the FE as well as they both use the same runtime.

The codec still have different constraints depending on the interface format, so I replaced the constraint with a fixup function to make sure that the codec will not advertise non supported formats.

Is this a know feature?

Another thing which I have came across is the lack of support for parallel data pins in ASoC core. For example the soc-pcm only checks the tdm slots to fix up the channels supported by the codec, but when we have multiple pins in use and they are operate in parallel, then the number of slots must be multiplied by the data pins in use. I have wip patches for this, adding

int snd_soc_dai_set_data_pins(struct snd_soc_dai *dai, unsigned int tx_data_pins, unsigned int rx_data_pins);

and then using the information in soc-pcm, but need to check further to see if there are other places this might be needed.

Regards, Peter

sound/soc/codecs/pcm3168a.c | 98 +++++++++++++++---------------------- 1 file changed, 40 insertions(+), 58 deletions(-)

diff --git a/sound/soc/codecs/pcm3168a.c b/sound/soc/codecs/pcm3168a.c index 88b75695fbf7..708dac27feff 100644 --- a/sound/soc/codecs/pcm3168a.c +++ b/sound/soc/codecs/pcm3168a.c @@ -62,6 +62,7 @@ struct pcm3168a_priv { unsigned long sysclk;

struct pcm3168a_io_params io_params[2]; + struct snd_soc_dai_driver dai_drv[2]; };

static const char *const pcm3168a_roll_off[] = { "Sharp", "Slow" }; @@ -314,6 +315,37 @@ static int pcm3168a_set_dai_sysclk(struct snd_soc_dai *dai, return 0; }

+static void pcm3168a_update_fixup_pcm_stream(struct snd_soc_dai *dai) +{ + struct snd_soc_component *component = dai->component; + struct pcm3168a_priv *pcm3168a = snd_soc_component_get_drvdata(component); + u64 formats = SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_LE; + unsigned int channel_max = dai->id == PCM3168A_DAI_DAC ? 8 : 6; + + if (!pcm3168a->io_params[dai->id].fmt) + return; + + if (pcm3168a->io_params[dai->id].fmt == PCM3168A_FMT_RIGHT_J) { + /* S16_LE is only supported in RIGHT_J mode */ + formats |= SNDRV_PCM_FMTBIT_S16_LE; + + /* + * If multi DIN/DOUT is not selected, RIGHT_J can only support + * two channels (no TDM support) + */ + if (pcm3168a->io_params[dai->id].tdm_slots != 2) + channel_max = 2; + } + + if (dai->id == PCM3168A_DAI_DAC) { + dai->driver->playback.channels_max = channel_max; + dai->driver->playback.formats = formats; + } else { + dai->driver->capture.channels_max = channel_max; + dai->driver->capture.formats = formats; + } +} + static int pcm3168a_set_dai_fmt(struct snd_soc_dai *dai, unsigned int format) { struct snd_soc_component *component = dai->component; @@ -376,6 +408,8 @@ static int pcm3168a_set_dai_fmt(struct snd_soc_dai *dai, unsigned int format)

regmap_update_bits(pcm3168a->regmap, reg, mask, fmt << shift);

+ pcm3168a_update_fixup_pcm_stream(dai); + return 0; }

@@ -409,6 +443,8 @@ static int pcm3168a_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx_mask, else io_params->tdm_mask = rx_mask;

+ pcm3168a_update_fixup_pcm_stream(dai); + return 0; }

@@ -530,63 +566,7 @@ static int pcm3168a_hw_params(struct snd_pcm_substream *substream, return 0; }

-static int pcm3168a_startup(struct snd_pcm_substream *substream, - struct snd_soc_dai *dai) -{ - struct snd_soc_component *component = dai->component; - struct pcm3168a_priv *pcm3168a = snd_soc_component_get_drvdata(component); - unsigned int sample_min; - unsigned int channel_max; - unsigned int channel_maxs[] = { - 8, /* DAC */ - 6 /* ADC */ - }; - - /* - * Available Data Bits - * - * RIGHT_J : 24 / 16 - * LEFT_J : 24 - * I2S : 24 - * - * TDM available - * - * I2S - * LEFT_J - */ - switch (pcm3168a->io_params[dai->id].fmt) { - case PCM3168A_FMT_RIGHT_J: - sample_min = 16; - channel_max = 2; - break; - case PCM3168A_FMT_LEFT_J: - case PCM3168A_FMT_I2S: - case PCM3168A_FMT_DSP_A: - case PCM3168A_FMT_DSP_B: - sample_min = 24; - channel_max = channel_maxs[dai->id]; - break; - default: - sample_min = 24; - channel_max = 2; - } - - snd_pcm_hw_constraint_minmax(substream->runtime, - SNDRV_PCM_HW_PARAM_SAMPLE_BITS, - sample_min, 32); - - /* Allow all channels in multi DIN/DOUT mode */ - if (pcm3168a->io_params[dai->id].tdm_slots == 2) - channel_max = channel_maxs[dai->id]; - - snd_pcm_hw_constraint_minmax(substream->runtime, - SNDRV_PCM_HW_PARAM_CHANNELS, - 2, channel_max); - - return 0; -} static const struct snd_soc_dai_ops pcm3168a_dai_ops = { - .startup = pcm3168a_startup, .set_fmt = pcm3168a_set_dai_fmt, .set_sysclk = pcm3168a_set_dai_sysclk, .hw_params = pcm3168a_hw_params, @@ -776,8 +756,10 @@ int pcm3168a_probe(struct device *dev, struct regmap *regmap) pm_runtime_enable(dev); pm_runtime_idle(dev);

- ret = devm_snd_soc_register_component(dev, &pcm3168a_driver, pcm3168a_dais, - ARRAY_SIZE(pcm3168a_dais)); + memcpy(pcm3168a->dai_drv, pcm3168a_dais, sizeof(pcm3168a->dai_drv)); + ret = devm_snd_soc_register_component(dev, &pcm3168a_driver, + pcm3168a->dai_drv, + ARRAY_SIZE(pcm3168a->dai_drv)); if (ret) { dev_err(dev, "failed to register component: %d\n", ret); goto err_regulator;