ASoC: Add utility to parse DAPM routes from device tree

Implement snd_soc_of_parse_audio_routing(), a utility function that can
parses a simple DAPM route table from device tree.The machine driver
specifies the DT property to use, since this is binding-specific.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 59 insertions, 0 deletions

diff --git a/include/sound/soc.h b/include/sound/soc.h
index 278f3b892ca6..db8acd299043 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -963,6 +963,8 @@ void snd_soc_util_exit(void);
 
 int snd_soc_of_parse_card_name(struct snd_soc_card *card,
                                const char *propname);
+int snd_soc_of_parse_audio_routing(struct snd_soc_card *card,
+                                   const char *propname);
 
 #include <sound/soc-dai.h>
 
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 51eef9b7b53f..42ad2db8f082 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -3342,6 +3342,63 @@ int snd_soc_of_parse_card_name(struct snd_soc_card *card,
 }
 EXPORT_SYMBOL_GPL(snd_soc_of_parse_card_name);
 
+int snd_soc_of_parse_audio_routing(struct snd_soc_card *card,
+                                   const char *propname)
+{
+        struct device_node *np = card->dev->of_node;
+        int num_routes;
+        struct snd_soc_dapm_route *routes;
+        int i, ret;
+
+        num_routes = of_property_count_strings(np, propname);
+        if (num_routes & 1) {
+                dev_err(card->dev,
+                        "Property '%s's length is not even\n",
+                        propname);
+                return -EINVAL;
+        }
+        num_routes /= 2;
+        if (!num_routes) {
+                dev_err(card->dev,
+                        "Property '%s's length is zero\n",
+                        propname);
+                return -EINVAL;
+        }
+
+        routes = devm_kzalloc(card->dev, num_routes * sizeof(*routes),
+                              GFP_KERNEL);
+        if (!routes) {
+                dev_err(card->dev,
+                        "Could not allocate DAPM route table\n");
+                return -EINVAL;
+        }
+
+        for (i = 0; i < num_routes; i++) {
+                ret = of_property_read_string_index(np, propname,
+                        2 * i, &routes[i].sink);
+                if (ret) {
+                        dev_err(card->dev,
+                                "Property '%s' index %d could not be read: %d\n",
+                                propname, 2 * i, ret);
+                        return -EINVAL;
+                }
+                ret = of_property_read_string_index(np, propname,
+                        (2 * i) + 1, &routes[i].source);
+                if (ret) {
+                        dev_err(card->dev,
+                                "Property '%s' index %d could not be read: %d\n",
+                                propname, (2 * i) + 1, ret);
+                        return -EINVAL;
+                }
+        }
+
+        card->num_dapm_routes = num_routes;
+        card->dapm_routes = routes;
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_of_parse_audio_routing);
+
 static int __init snd_soc_init(void)
 {
 #ifdef CONFIG_DEBUG_FS