ASoC: hdmi-codec: add .get_dai_id support

ALSA SoC needs to know connected DAI ID for probing.
It is not a big problem if device/driver was only for sound,
but getting DAI ID will be difficult if device includes both
Video/Sound, like HDMI.
To solve this issue, this patch adds new .get_dai_id callback
on hdmi_codec_ops

Signed-off-by: Kuninori Morimoto <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

include/sound/hdmi-codec.h

···
 #ifndef __HDMI_CODEC_H__
 #define __HDMI_CODEC_H__
 
+#include <linux/of_graph.h>
 #include <linux/hdmi.h>
 #include <drm/drm_edid.h>
 #include <sound/asoundef.h>
+#include <sound/soc.h>
 #include <uapi/sound/asound.h>
 
 /*
···
 	 */
 	int (*get_eld)(struct device *dev, void *data,
 		       uint8_t *buf, size_t len);
+
+	/*
+	 * Getting DAI ID
+	 * Optional
+	 */
+	int (*get_dai_id)(struct snd_soc_component *comment,
+			  struct device_node *endpoint);
 };
 
 /* HDMI codec initalization data */

sound/soc/codecs/hdmi-codec.c

···
 	.pcm_new = hdmi_codec_pcm_new,
 };
 
+static int hdmi_of_xlate_dai_id(struct snd_soc_component *component,
+				 struct device_node *endpoint)
+{
+	struct hdmi_codec_priv *hcp = snd_soc_component_get_drvdata(component);
+	int ret = -ENOTSUPP; /* see snd_soc_get_dai_id() */
+
+	if (hcp->hcd.ops->get_dai_id)
+		ret = hcp->hcd.ops->get_dai_id(component, endpoint);
+
+	return ret;
+}
+
 static struct snd_soc_codec_driver hdmi_codec = {
 	.component_driver = {
 		.controls		= hdmi_controls,
···
 		.num_dapm_widgets	= ARRAY_SIZE(hdmi_widgets),
 		.dapm_routes		= hdmi_routes,
 		.num_dapm_routes	= ARRAY_SIZE(hdmi_routes),
+		.of_xlate_dai_id	= hdmi_of_xlate_dai_id,
 	},
 };