ASoC: add snd_soc_get_dai_id() function

ALSA SoC needs to know connected DAI ID for detecting.
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 snd_soc_get_dai_id() and
its related .of_xlate_dai_id callback on component driver.
In below case, we can handle Sound port (= port@2) as ID = 0
if .of_xlate_dai_id has its support.

	hdmi {
		port@0 { /* VIDEO */ };
		port@1 { /* VIDEO */ };
		port@2 { /* SOUND */ };
	};

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

include/sound/soc.h

@@ -803,6 +803,8 @@ struct snd_soc_component_driver {
 	int (*of_xlate_dai_name)(struct snd_soc_component *component,
 				 struct of_phandle_args *args,
 				 const char **dai_name);
+	int (*of_xlate_dai_id)(struct snd_soc_component *comment,
+			       struct device_node *endpoint);
 	void (*seq_notifier)(struct snd_soc_component *, enum snd_soc_dapm_type,
 		int subseq);
 	int (*stream_event)(struct snd_soc_component *, int event);
@@ -1676,6 +1678,7 @@ unsigned int snd_soc_of_parse_daifmt(struct device_node *np,
 				     const char *prefix,
 				     struct device_node **bitclkmaster,
 				     struct device_node **framemaster);
+int snd_soc_get_dai_id(struct device_node *ep);
 int snd_soc_get_dai_name(struct of_phandle_args *args,
 			 const char **dai_name);
 int snd_soc_of_get_dai_name(struct device_node *of_node,

sound/soc/soc-core.c

@@ -34,6 +34,7 @@
 #include <linux/ctype.h>
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/dmi.h>
 #include <sound/core.h>
 #include <sound/jack.h>
@@ -4044,6 +4045,42 @@ unsigned int snd_soc_of_parse_daifmt(struct device_node *np,
 }
 EXPORT_SYMBOL_GPL(snd_soc_of_parse_daifmt);
 
+int snd_soc_get_dai_id(struct device_node *ep)
+{
+	struct snd_soc_component *pos;
+	struct device_node *node;
+	int ret;
+
+	node = of_graph_get_port_parent(ep);
+
+	/*
+	 * For example HDMI case, HDMI has video/sound port,
+	 * but ALSA SoC needs sound port number only.
+	 * Thus counting HDMI DT port/endpoint doesn't work.
+	 * Then, it should have .of_xlate_dai_id
+	 */
+	ret = -ENOTSUPP;
+	mutex_lock(&client_mutex);
+	list_for_each_entry(pos, &component_list, list) {
+		struct device_node *component_of_node = pos->dev->of_node;
+
+		if (!component_of_node && pos->dev->parent)
+			component_of_node = pos->dev->parent->of_node;
+
+		if (component_of_node != node)
+			continue;
+
+		if (pos->driver->of_xlate_dai_id)
+			ret = pos->driver->of_xlate_dai_id(pos, ep);
+
+		break;
+	}
+	mutex_unlock(&client_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_soc_get_dai_id);
+
 int snd_soc_get_dai_name(struct of_phandle_args *args,
 				const char **dai_name)
 {