ASoC: core: add multi-codec support in DT

This patch exports a core function which handles the DT description
of multi-codec links (as: "sound-dai = <&hdmi 0>, <&spdif_codec>;")
and creates a CODEC component array in the DAI link.
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>

include/sound/soc.h

@@ -1451,6 +1451,9 @@ unsigned int snd_soc_of_parse_daifmt(struct device_node *np,
 				     struct device_node **framemaster);
 int snd_soc_of_get_dai_name(struct device_node *of_node,
 			    const char **dai_name);
+int snd_soc_of_get_dai_link_codecs(struct device *dev,
+				   struct device_node *of_node,
+				   struct snd_soc_dai_link *dai_link);
 
 #include <sound/soc-dai.h>
 

sound/soc/soc-core.c

@@ -4750,36 +4750,30 @@ unsigned int snd_soc_of_parse_daifmt(struct device_node *np,
 }
 EXPORT_SYMBOL_GPL(snd_soc_of_parse_daifmt);
 
-int snd_soc_of_get_dai_name(struct device_node *of_node,
-			    const char **dai_name)
+static int snd_soc_get_dai_name(struct of_phandle_args *args,
+				const char **dai_name)
 {
 	struct snd_soc_component *pos;
-	struct of_phandle_args args;
-	int ret;
-
-	ret = of_parse_phandle_with_args(of_node, "sound-dai",
-					 "#sound-dai-cells", 0, &args);
-	if (ret)
-		return ret;
-
-	ret = -EPROBE_DEFER;
+	int ret = -EPROBE_DEFER;
 
 	mutex_lock(&client_mutex);
 	list_for_each_entry(pos, &component_list, list) {
-		if (pos->dev->of_node != args.np)
+		if (pos->dev->of_node != args->np)
 			continue;
 
 		if (pos->driver->of_xlate_dai_name) {
-			ret = pos->driver->of_xlate_dai_name(pos, &args, dai_name);
+			ret = pos->driver->of_xlate_dai_name(pos,
+							     args,
+							     dai_name);
 		} else {
 			int id = -1;
 
-			switch (args.args_count) {
+			switch (args->args_count) {
 			case 0:
 				id = 0; /* same as dai_drv[0] */
 				break;
 			case 1:
-				id = args.args[0];
+				id = args->args[0];
 				break;
 			default:
 				/* not supported */
@@ -4801,6 +4795,21 @@ int snd_soc_of_get_dai_name(struct device_node *of_node,
 		break;
 	}
 	mutex_unlock(&client_mutex);
+	return ret;
+}
+
+int snd_soc_of_get_dai_name(struct device_node *of_node,
+			    const char **dai_name)
+{
+	struct of_phandle_args args;
+	int ret;
+
+	ret = of_parse_phandle_with_args(of_node, "sound-dai",
+					 "#sound-dai-cells", 0, &args);
+	if (ret)
+		return ret;
+
+	ret = snd_soc_get_dai_name(&args, dai_name);
 
 	of_node_put(args.np);
 
@@ -4808,6 +4817,77 @@ int snd_soc_of_get_dai_name(struct device_node *of_node,
 }
 EXPORT_SYMBOL_GPL(snd_soc_of_get_dai_name);
 
+/*
+ * snd_soc_of_get_dai_link_codecs - Parse a list of CODECs in the devicetree
+ * @dev: Card device
+ * @of_node: Device node
+ * @dai_link: DAI link
+ *
+ * Builds an array of CODEC DAI components from the DAI link property
+ * 'sound-dai'.
+ * The array is set in the DAI link and the number of DAIs is set accordingly.
+ * The device nodes in the array (of_node) must be dereferenced by the caller.
+ *
+ * Returns 0 for success
+ */
+int snd_soc_of_get_dai_link_codecs(struct device *dev,
+				   struct device_node *of_node,
+				   struct snd_soc_dai_link *dai_link)
+{
+	struct of_phandle_args args;
+	struct snd_soc_dai_link_component *component;
+	char *name;
+	int index, num_codecs, ret;
+
+	/* Count the number of CODECs */
+	name = "sound-dai";
+	num_codecs = of_count_phandle_with_args(of_node, name,
+						"#sound-dai-cells");
+	if (num_codecs <= 0) {
+		if (num_codecs == -ENOENT)
+			dev_err(dev, "No 'sound-dai' property\n");
+		else
+			dev_err(dev, "Bad phandle in 'sound-dai'\n");
+		return num_codecs;
+	}
+	component = devm_kzalloc(dev,
+				 sizeof *component * num_codecs,
+				 GFP_KERNEL);
+	if (!component)
+		return -ENOMEM;
+	dai_link->codecs = component;
+	dai_link->num_codecs = num_codecs;
+
+	/* Parse the list */
+	for (index = 0, component = dai_link->codecs;
+	     index < dai_link->num_codecs;
+	     index++, component++) {
+		ret = of_parse_phandle_with_args(of_node, name,
+						 "#sound-dai-cells",
+						  index, &args);
+		if (ret)
+			goto err;
+		component->of_node = args.np;
+		ret = snd_soc_get_dai_name(&args, &component->dai_name);
+		if (ret < 0)
+			goto err;
+	}
+	return 0;
+err:
+	for (index = 0, component = dai_link->codecs;
+	     index < dai_link->num_codecs;
+	     index++, component++) {
+		if (!component->of_node)
+			break;
+		of_node_put(component->of_node);
+		component->of_node = NULL;
+	}
+	dai_link->codecs = NULL;
+	dai_link->num_codecs = 0;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_soc_of_get_dai_link_codecs);
+
 static int __init snd_soc_init(void)
 {
 #ifdef CONFIG_DEBUG_FS