ASoC: Add CODEC volatile register operation

Add a volatile_register() operation to the CODEC structure providing a
standard operation to query if a register is volatile. This will be used
to factor out the register cache I/O operations for the CODECs.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 19 insertions, 0 deletions

diff --git a/include/sound/soc.h b/include/sound/soc.h
index e6704c0a4404..94fcc65609b6 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -191,6 +191,7 @@ int snd_soc_register_platform(struct snd_soc_platform *platform);
 void snd_soc_unregister_platform(struct snd_soc_platform *platform);
 int snd_soc_register_codec(struct snd_soc_codec *codec);
 void snd_soc_unregister_codec(struct snd_soc_codec *codec);
+int snd_soc_codec_volatile_register(struct snd_soc_codec *codec, int reg);
 
 #ifdef CONFIG_PM
 int snd_soc_suspend_device(struct device *dev);
@@ -361,6 +362,7 @@ struct snd_soc_codec {
         int (*write)(struct snd_soc_codec *, unsigned int, unsigned int);
         int (*display_register)(struct snd_soc_codec *, char *,
                                 size_t, unsigned int);
+        int (*volatile_register)(unsigned int);
         hw_write_t hw_write;
         hw_read_t hw_read;
         void *reg_cache;
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index dfc03c0bacb6..8bf49a4e664a 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1125,6 +1125,23 @@ static int soc_new_pcm(struct snd_soc_device *socdev,
         return ret;
 }
 
+/**
+ * snd_soc_codec_volatile_register: Report if a register is volatile.
+ *
+ * @codec: CODEC to query.
+ * @reg: Register to query.
+ *
+ * Boolean function indiciating if a CODEC register is volatile.
+ */
+int snd_soc_codec_volatile_register(struct snd_soc_codec *codec, int reg)
+{
+        if (codec->volatile_register)
+                return codec->volatile_register(reg);
+        else
+                return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_codec_volatile_register);
+
 /* codec register dump */
 static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf)
 {