ASoC: core: Support for limiting the volume

[deliverable/linux.git] / sound / soc / soc-core.c

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index d59076e2ca84d404f0ed76421be709b6232b5209..4079223203eb8bdb5684282819c27b3e118a9e79 100644 (file)
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2237,6 +2237,45 @@ int snd_soc_put_volsw_s8(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_GPL(snd_soc_put_volsw_s8);
 
+/**
+ * snd_soc_limit_volume - Set new limit to an existing volume control.
+ *
+ * @codec: where to look for the control
+ * @name: Name of the control
+ * @max: new maximum limit
+ *
+ * Return 0 for success, else error.
+ */
+int snd_soc_limit_volume(struct snd_soc_codec *codec,
+       const char *name, int max)
+{
+       struct snd_card *card = codec->card;
+       struct snd_kcontrol *kctl;
+       struct soc_mixer_control *mc;
+       int found = 0;
+       int ret = -EINVAL;
+
+       /* Sanity check for name and max */
+       if (unlikely(!name || max <= 0))
+               return -EINVAL;
+
+       list_for_each_entry(kctl, &card->controls, list) {
+               if (!strncmp(kctl->id.name, name, sizeof(kctl->id.name))) {
+                       found = 1;
+                       break;
+               }
+       }
+       if (found) {
+               mc = (struct soc_mixer_control *)kctl->private_value;
+               if (max <= mc->max) {
+                       mc->max = max;
+                       ret = 0;
+               }
+       }
+       return ret;
+}
+EXPORT_SYMBOL_GPL(snd_soc_limit_volume);
+
 /**
  * snd_soc_dai_set_sysclk - configure DAI system or master clock.
  * @dai: DAI