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Subject[PATCH v8 1/2] ASoC: hdmi: Add a transmitter interface to the HDMI CODEC
Audio in HDMI asks for:
- the audio constraints of the HDMI device to be known when choosing
the audio routes in the audio subsystem, and
- the HDMI transmitter to know which of its audio inputs has been
chosen when audio streaming starts.

This patch adds the interface between a HDMI transmitter and the
HDMI CODEC.

At startup time, the HDMI transmitter device creates the HDMI device as
a child device giving a description of its DAIs and 2 callback functions,
these functions realizing the HDMI audio requirements.

Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
---
include/sound/hdmi.h | 20 ++++++
sound/soc/codecs/hdmi.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 190 insertions(+), 6 deletions(-)
create mode 100644 include/sound/hdmi.h

diff --git a/include/sound/hdmi.h b/include/sound/hdmi.h
new file mode 100644
index 0000000..49062c7
--- /dev/null
+++ b/include/sound/hdmi.h
@@ -0,0 +1,20 @@
+#ifndef SND_HDMI_H
+#define SND_HDMI_H
+
+#include <sound/soc.h>
+
+/* platform_data */
+struct hdmi_data {
+ int (*get_audio)(struct device *dev,
+ int *max_channels,
+ int *rate_mask,
+ int *fmt);
+ void (*audio_switch)(struct device *dev,
+ int port_index,
+ unsigned sample_rate,
+ int sample_format);
+ int ndais;
+ struct snd_soc_dai_driver *dais;
+ struct snd_soc_codec_driver *driver;
+};
+#endif
diff --git a/sound/soc/codecs/hdmi.c b/sound/soc/codecs/hdmi.c
index 1391ad5..f66f1f6 100644
--- a/sound/soc/codecs/hdmi.c
+++ b/sound/soc/codecs/hdmi.c
@@ -22,9 +22,148 @@
#include <sound/soc.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <sound/pcm_params.h>
+#include <sound/hdmi.h>

#define DRV_NAME "hdmi-audio-codec"

+struct hdmi_priv {
+ struct hdmi_data hdmi_data;
+ struct snd_pcm_hw_constraint_list rate_constraints;
+};
+
+static int hdmi_dev_match(struct device *dev, void *data)
+{
+ return !strcmp(dev_name(dev), (char *) data);
+}
+
+/* get the codec device */
+static struct device *hdmi_get_cdev(struct device *dev)
+{
+ struct device *cdev;
+
+ cdev = device_find_child(dev,
+ DRV_NAME,
+ hdmi_dev_match);
+ if (!cdev)
+ dev_err(dev, "Cannot get codec device");
+ else
+ put_device(cdev);
+ return cdev;
+}
+
+static int hdmi_startup(struct snd_pcm_substream *substream,
+ struct snd_soc_dai *dai)
+{
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct device *cdev;
+ struct hdmi_priv *priv;
+ struct snd_pcm_hw_constraint_list *rate_constraints;
+ int ret, max_channels, rate_mask, fmt;
+ u64 formats;
+ static const u32 hdmi_rates[] = {
+ 32000, 44100, 48000, 88200, 96000, 176400, 192000
+ };
+
+ cdev = hdmi_get_cdev(dai->dev);
+ if (!cdev)
+ return -ENODEV;
+ priv = dev_get_drvdata(cdev);
+
+ /* get the EDID values and the rate constraints buffer */
+ ret = priv->hdmi_data.get_audio(dai->dev,
+ &max_channels, &rate_mask, &fmt);
+ if (ret < 0)
+ return ret; /* no screen */
+
+ /* convert the EDID values to audio constraints */
+ rate_constraints = &priv->rate_constraints;
+ rate_constraints->list = hdmi_rates;
+ rate_constraints->count = ARRAY_SIZE(hdmi_rates);
+ rate_constraints->mask = rate_mask;
+ snd_pcm_hw_constraint_list(runtime, 0,
+ SNDRV_PCM_HW_PARAM_RATE,
+ rate_constraints);
+
+ formats = 0;
+ if (fmt & 1)
+ formats |= SNDRV_PCM_FMTBIT_S16_LE;
+ if (fmt & 2)
+ formats |= SNDRV_PCM_FMTBIT_S20_3LE;
+ if (fmt & 4)
+ formats |= SNDRV_PCM_FMTBIT_S24_LE |
+ SNDRV_PCM_FMTBIT_S24_3LE |
+ SNDRV_PCM_FMTBIT_S32_LE;
+ snd_pcm_hw_constraint_mask64(runtime,
+ SNDRV_PCM_HW_PARAM_FORMAT,
+ formats);
+
+ snd_pcm_hw_constraint_minmax(runtime,
+ SNDRV_PCM_HW_PARAM_CHANNELS,
+ 1, max_channels);
+ return 0;
+}
+
+static int hdmi_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *params,
+ struct snd_soc_dai *dai)
+{
+ struct device *cdev;
+ struct hdmi_priv *priv;
+
+ cdev = hdmi_get_cdev(dai->dev);
+ if (!cdev)
+ return -ENODEV;
+ priv = dev_get_drvdata(cdev);
+
+ priv->hdmi_data.audio_switch(dai->dev, dai->id,
+ params_rate(params),
+ params_format(params));
+ return 0;
+}
+
+static void hdmi_shutdown(struct snd_pcm_substream *substream,
+ struct snd_soc_dai *dai)
+{
+ struct device *cdev;
+ struct hdmi_priv *priv;
+
+ cdev = hdmi_get_cdev(dai->dev);
+ if (!cdev)
+ return;
+ priv = dev_get_drvdata(cdev);
+
+ priv->hdmi_data.audio_switch(dai->dev, -1, 0, 0); /* stop */
+}
+
+static const struct snd_soc_dai_ops hdmi_ops = {
+ .startup = hdmi_startup,
+ .hw_params = hdmi_hw_params,
+ .shutdown = hdmi_shutdown,
+};
+
+static int hdmi_codec_probe(struct snd_soc_codec *codec)
+{
+ struct hdmi_priv *priv;
+ struct device *dev = codec->dev; /* encoder device */
+ struct device *cdev; /* codec device */
+
+ cdev = hdmi_get_cdev(dev);
+ if (!cdev)
+ return -ENODEV;
+
+ /* allocate some memory to store
+ * the encoder callback functions and the rate constraints */
+ priv = devm_kzalloc(cdev, sizeof *priv, GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ dev_set_drvdata(cdev, priv);
+
+ memcpy(&priv->hdmi_data, cdev->platform_data,
+ sizeof priv->hdmi_data);
+ return 0;
+}
+
static const struct snd_soc_dapm_widget hdmi_widgets[] = {
SND_SOC_DAPM_INPUT("RX"),
SND_SOC_DAPM_OUTPUT("TX"),
@@ -79,13 +218,38 @@ static struct snd_soc_codec_driver hdmi_codec = {
.ignore_pmdown_time = true,
};

-static int hdmi_codec_probe(struct platform_device *pdev)
+static int hdmi_codec_dev_probe(struct platform_device *pdev)
{
- return snd_soc_register_codec(&pdev->dev, &hdmi_codec,
- &hdmi_codec_dai, 1);
+ struct hdmi_data *pdata = pdev->dev.platform_data;
+ struct snd_soc_dai_driver *dais;
+ struct snd_soc_codec_driver *driver;
+ int i, ret;
+
+ if (!pdata)
+ return snd_soc_register_codec(&pdev->dev, &hdmi_codec,
+ &hdmi_codec_dai, 1);
+
+ /* creation from a video encoder as a child device */
+ dais = devm_kmemdup(&pdev->dev,
+ pdata->dais,
+ sizeof *pdata->dais * pdata->ndais,
+ GFP_KERNEL);
+ for (i = 0; i < pdata->ndais; i++)
+ dais[i].ops = &hdmi_ops;
+
+ driver = devm_kmemdup(&pdev->dev,
+ pdata->driver,
+ sizeof *pdata->driver,
+ GFP_KERNEL);
+ driver->probe = hdmi_codec_probe;
+
+ /* register the codec on the video encoder */
+ ret = snd_soc_register_codec(pdev->dev.parent, driver,
+ dais, pdata->ndais);
+ return ret;
}

-static int hdmi_codec_remove(struct platform_device *pdev)
+static int hdmi_codec_dev_remove(struct platform_device *pdev)
{
snd_soc_unregister_codec(&pdev->dev);
return 0;
@@ -98,8 +262,8 @@ static struct platform_driver hdmi_codec_driver = {
.of_match_table = of_match_ptr(hdmi_audio_codec_ids),
},

- .probe = hdmi_codec_probe,
- .remove = hdmi_codec_remove,
+ .probe = hdmi_codec_dev_probe,
+ .remove = hdmi_codec_dev_remove,
};

module_platform_driver(hdmi_codec_driver);
--
2.1.1


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