[alsa-devel] [RFC v3 7/7] ASoC: hdmi-codec: Add ELD control

[Jyri Sarha]

On 01/12/16 17:38, Philipp Zabel wrote:
> Exporting the ELD bytes to userspace allows an application to select
> an appropriate audio format depending on the current capabilities of
> the connected HDMI sink device.
>

This looks good, but I was unable to test it. Obviously amixer or 
alsamixer is unable to show anything about an ELD mixer element, but 
shouldn't there be something about it shown under /proc/asound/card0/, 
or am I mistaken.

Cheers,
Jyri

> Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
> ---
>   sound/soc/codecs/hdmi-codec.c | 36 ++++++++++++++++++++++++++++++++++++
>   1 file changed, 36 insertions(+)
>
> diff --git a/sound/soc/codecs/hdmi-codec.c b/sound/soc/codecs/hdmi-codec.c
> index 6b327e2..6cb7217 100644
> --- a/sound/soc/codecs/hdmi-codec.c
> +++ b/sound/soc/codecs/hdmi-codec.c
> @@ -54,6 +54,40 @@ enum {
>   	DAI_ID_SPDIF,
>   };
>
> +static int hdmi_eld_ctl_info(struct snd_kcontrol *kcontrol,
> +			     struct snd_ctl_elem_info *uinfo)
> +{
> +	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
> +	struct hdmi_codec_priv *hcp = snd_soc_component_get_drvdata(component);
> +
> +	uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
> +	uinfo->count = sizeof(hcp->eld);
> +
> +	return 0;
> +}
> +
> +static int hdmi_eld_ctl_get(struct snd_kcontrol *kcontrol,
> +			    struct snd_ctl_elem_value *ucontrol)
> +{
> +	struct snd_soc_component *component = snd_kcontrol_chip(kcontrol);
> +	struct hdmi_codec_priv *hcp = snd_soc_component_get_drvdata(component);
> +
> +	memcpy(ucontrol->value.bytes.data, hcp->eld, sizeof(hcp->eld));
> +
> +	return 0;
> +}
> +
> +static const struct snd_kcontrol_new hdmi_controls[] = {
> +	{
> +		.access = SNDRV_CTL_ELEM_ACCESS_READ |
> +			  SNDRV_CTL_ELEM_ACCESS_VOLATILE,
> +		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
> +		.name = "ELD",
> +		.info = hdmi_eld_ctl_info,
> +		.get = hdmi_eld_ctl_get,
> +	},
> +};
> +
>   static void hdmi_codec_abort(struct device *dev)
>   {
>   	struct hdmi_codec_priv *hcp = dev_get_drvdata(dev);
> @@ -327,6 +361,8 @@ static const struct snd_soc_dai_driver hdmi_spdif_dai = {
>   };
>
>   static struct snd_soc_codec_driver hdmi_codec = {
> +	.controls = hdmi_controls,
> +	.num_controls = ARRAY_SIZE(hdmi_controls),
>   	.dapm_widgets = hdmi_widgets,
>   	.num_dapm_widgets = ARRAY_SIZE(hdmi_widgets),
>   	.dapm_routes = hdmi_routes,
>