ASoC: Add I/O control bus information to factored out cache setup

While writes tend to be able to use a fairly bus independant format to
do the writes reads are all bus specific. To allow us to factor out
this code include the bus type as a parameter when setting up the
cache.

Initially just use this to factor out hw_write_t for I2C.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index 27409dd..d0b29a5 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -187,13 +187,20 @@
 
 extern struct snd_ac97_bus_ops soc_ac97_ops;
 
+enum snd_soc_control_type {
+	SND_SOC_CUSTOM,
+	SND_SOC_I2C,
+	SND_SOC_SPI,
+};
+
 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);
 int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
-			       int addr_bits, int data_bits);
+			       int addr_bits, int data_bits,
+			       enum snd_soc_control_type control);
 
 #ifdef CONFIG_PM
 int snd_soc_suspend_device(struct device *dev);