ASoC: Add utility to set a card's name from device tree

Implement snd_soc_of_parse_card_name(), a utility function that sets a
card's name 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, 28 insertions, 0 deletions

diff --git a/include/sound/soc.h b/include/sound/soc.h
index a35cf14a8eb1..278f3b892ca6 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -961,6 +961,9 @@ static inline bool snd_soc_volsw_is_stereo(struct soc_mixer_control *mc)
 int snd_soc_util_init(void);
 void snd_soc_util_exit(void);
 
+int snd_soc_of_parse_card_name(struct snd_soc_card *card,
+                               const char *propname);
+
 #include <sound/soc-dai.h>
 
 #ifdef CONFIG_DEBUG_FS
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 1252ab1ebf69..51eef9b7b53f 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -32,6 +32,7 @@
 #include <linux/platform_device.h>
 #include <linux/ctype.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 #include <sound/ac97_codec.h>
 #include <sound/core.h>
 #include <sound/jack.h>
@@ -3317,6 +3318,30 @@ found:
 }
 EXPORT_SYMBOL_GPL(snd_soc_unregister_codec);
 
+/* Retrieve a card's name from device tree */
+int snd_soc_of_parse_card_name(struct snd_soc_card *card,
+                               const char *propname)
+{
+        struct device_node *np = card->dev->of_node;
+        int ret;
+
+        ret = of_property_read_string_index(np, propname, 0, &card->name);
+        /*
+         * EINVAL means the property does not exist. This is fine providing
+         * card->name was previously set, which is checked later in
+         * snd_soc_register_card.
+         */
+        if (ret < 0 && ret != -EINVAL) {
+                dev_err(card->dev,
+                        "Property '%s' could not be read: %d\n",
+                        propname, ret);
+                return ret;
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_of_parse_card_name);
+
 static int __init snd_soc_init(void)
 {
 #ifdef CONFIG_DEBUG_FS