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

[Philipp Zabel]

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.

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,
-- 
2.6.4