On Thu 13 Feb 2020 at 07:11, Samuel Holland <samuel@xxxxxxxxxxxx> wrote: > For now we assume there are only a few sets of valid PCM stream > parameters, to avoid needing to specify them in the device tree. We > also assume they are the same in both directions. We calculate the > common subset of parameters, and then the existing code automatically > chooses the highest quality of the remaining values. > > Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx> > --- > .../devicetree/bindings/sound/simple-card.txt | 1 + > Documentation/sound/soc/codec-to-codec.rst | 9 ++++- > include/sound/simple_card_utils.h | 1 + > sound/soc/generic/simple-card-utils.c | 39 +++++++++++++++++++ > sound/soc/generic/simple-card.c | 12 ++++++ > 5 files changed, 60 insertions(+), 2 deletions(-) > > diff --git a/Documentation/devicetree/bindings/sound/simple-card.txt b/Documentation/devicetree/bindings/sound/simple-card.txt > index 79954cd6e37b..18a62e404a30 100644 > --- a/Documentation/devicetree/bindings/sound/simple-card.txt > +++ b/Documentation/devicetree/bindings/sound/simple-card.txt > @@ -63,6 +63,7 @@ Optional dai-link subnode properties: > - mclk-fs : Multiplication factor between stream > rate and codec mclk, applied only for > the dai-link. > +- codec-to-codec : Indicates a codec-to-codec > dai-link. I wonder if such property could be viewed as a Linux implementation detail ? Similar discussion around DPCM: * https://lore.kernel.org/linux-devicetree/20191014115635.GB4826@xxxxxxxxxxxx/#t * https://alsa-devel.alsa-project.narkive.com/NCs4MsqL/simle-card-dt-style-for-dpcm#post4 Should the card figure out the codec-to-codec links on its own or is it something generic enough to put in DT ? In the Amlogic card driver, I'm using the compatible string of the device to figure out if CPU is a CODEC. It is ad-hoc and, to be honest, I'm not entirely happy with this solution but I could not figure out a better one yet. > > For backward compatibility the frame-master and bitclock-master > properties can be used as booleans in codec subnode to indicate if the > diff --git a/Documentation/sound/soc/codec-to-codec.rst b/Documentation/sound/soc/codec-to-codec.rst > index 810109d7500d..efe0a8c07933 100644 > --- a/Documentation/sound/soc/codec-to-codec.rst > +++ b/Documentation/sound/soc/codec-to-codec.rst > @@ -104,5 +104,10 @@ Make sure to name your corresponding cpu and codec playback and capture > dai names ending with "Playback" and "Capture" respectively as dapm core > will link and power those dais based on the name. > > -Note that in current device tree there is no way to mark a dai_link > -as codec to codec. However, it may change in future. > +A dai_link in a "simple-audio-card" can be marked as codec to codec in > +the device tree by adding the "codec-to-codec" property. The dai_link > +will be initialized with the subset of stream parameters (channels, > +format, sample rate) supported by all DAIs on the link. Since there is > +no way to provide these parameters in the device tree, this is mostly > +useful for communication with simple fixed-function codecs, such as a > +Bluetooth controller or cellular modem. > diff --git a/include/sound/simple_card_utils.h b/include/sound/simple_card_utils.h > index bbdd1542d6f1..80b60237b3cd 100644 > --- a/include/sound/simple_card_utils.h > +++ b/include/sound/simple_card_utils.h > @@ -49,6 +49,7 @@ struct asoc_simple_priv { > struct asoc_simple_data adata; > struct snd_soc_codec_conf *codec_conf; > unsigned int mclk_fs; > + bool codec_to_codec; > } *dai_props; > struct asoc_simple_jack hp_jack; > struct asoc_simple_jack mic_jack; > diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c > index 9b794775df53..2de4cfead790 100644 > --- a/sound/soc/generic/simple-card-utils.c > +++ b/sound/soc/generic/simple-card-utils.c > @@ -331,6 +331,41 @@ static int asoc_simple_init_dai(struct snd_soc_dai *dai, > return 0; > } > > +static int asoc_simple_init_dai_link_params(struct snd_soc_pcm_runtime *rtd, > + struct simple_dai_props *dai_props) > +{ > + struct snd_soc_dai_link *dai_link = rtd->dai_link; > + struct snd_soc_pcm_stream *params; > + struct snd_pcm_hardware hw; > + int ret; > + > + if (!dai_props->codec_to_codec) > + return 0; > + > + /* Assumes the hardware capabilities are the same in both directions */ > + ret = snd_soc_runtime_calc_hw(rtd, &hw, SNDRV_PCM_STREAM_PLAYBACK); > + if (ret < 0) { > + dev_err(rtd->dev, "simple-card: no valid dai_link params\n"); > + return ret; > + } > + > + params = devm_kzalloc(rtd->dev, sizeof(*params), GFP_KERNEL); > + if (!params) > + return -ENOMEM; > + > + params->formats = hw.formats; > + params->rates = hw.rates; > + params->rate_min = hw.rate_min; > + params->rate_max = hw.rate_max; > + params->channels_min = hw.channels_min; > + params->channels_max = hw.channels_max; > + > + dai_link->params = params; > + dai_link->num_params = 1; > + > + return 0; > +} > + > int asoc_simple_dai_init(struct snd_soc_pcm_runtime *rtd) > { > struct asoc_simple_priv *priv = snd_soc_card_get_drvdata(rtd->card); > @@ -347,6 +382,10 @@ int asoc_simple_dai_init(struct snd_soc_pcm_runtime *rtd) > if (ret < 0) > return ret; > > + ret = asoc_simple_init_dai_link_params(rtd, dai_props); > + if (ret < 0) > + return ret; > + > return 0; > } > EXPORT_SYMBOL_GPL(asoc_simple_dai_init); > diff --git a/sound/soc/generic/simple-card.c b/sound/soc/generic/simple-card.c > index 55e9f8800b3e..179ab4482d10 100644 > --- a/sound/soc/generic/simple-card.c > +++ b/sound/soc/generic/simple-card.c > @@ -77,6 +77,16 @@ static int asoc_simple_parse_dai(struct device_node *node, > return 0; > } > > +static void simple_parse_codec_to_codec(struct device_node *node, > + struct simple_dai_props *props, > + char *prefix) > +{ > + char prop[128]; > + > + snprintf(prop, sizeof(prop), "%scodec-to-codec", prefix); > + props->codec_to_codec = of_property_read_bool(node, prop); > +} > + > static void simple_parse_convert(struct device *dev, > struct device_node *np, > struct asoc_simple_data *adata) > @@ -217,6 +227,7 @@ static int simple_dai_link_of_dpcm(struct asoc_simple_priv *priv, > "prefix"); > } > > + simple_parse_codec_to_codec(node, dai_props, prefix); > simple_parse_convert(dev, np, &dai_props->adata); > simple_parse_mclk_fs(top, np, codec, dai_props, prefix); > > @@ -292,6 +303,7 @@ static int simple_dai_link_of(struct asoc_simple_priv *priv, > if (ret < 0) > goto dai_link_of_err; > > + simple_parse_codec_to_codec(node, dai_props, prefix); > simple_parse_mclk_fs(top, cpu, codec, dai_props, prefix); > > ret = asoc_simple_parse_cpu(cpu, dai_link, &single_cpu);
