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/sound/soc/codecs/wm8731.c b/sound/soc/codecs/wm8731.c
index 4eb84ff..27fc942 100644
--- a/sound/soc/codecs/wm8731.c
+++ b/sound/soc/codecs/wm8731.c
@@ -504,7 +504,8 @@
 };
 EXPORT_SYMBOL_GPL(soc_codec_dev_wm8731);
 
-static int wm8731_register(struct wm8731_priv *wm8731)
+static int wm8731_register(struct wm8731_priv *wm8731,
+			   enum snd_soc_control_type control)
 {
 	int ret;
 	struct snd_soc_codec *codec = &wm8731->codec;
@@ -531,7 +532,7 @@
 
 	memcpy(codec->reg_cache, wm8731_reg, sizeof(wm8731_reg));
 
-	ret = snd_soc_codec_set_cache_io(codec, 7, 9);
+	ret = snd_soc_codec_set_cache_io(codec, 7, 9, control);
 	if (ret < 0) {
 		dev_err(codec->dev, "Failed to set cache I/O: %d\n", ret);
 		goto err;
@@ -630,7 +631,7 @@
 
 	dev_set_drvdata(&spi->dev, wm8731);
 
-	return wm8731_register(wm8731);
+	return wm8731_register(wm8731, SND_SOC_SPI);
 }
 
 static int __devexit wm8731_spi_remove(struct spi_device *spi)
@@ -682,14 +683,13 @@
 		return -ENOMEM;
 
 	codec = &wm8731->codec;
-	codec->hw_write = (hw_write_t)i2c_master_send;
 
 	i2c_set_clientdata(i2c, wm8731);
 	codec->control_data = i2c;
 
 	codec->dev = &i2c->dev;
 
-	return wm8731_register(wm8731);
+	return wm8731_register(wm8731, SND_SOC_I2C);
 }
 
 static __devexit int wm8731_i2c_remove(struct i2c_client *client)