ASoC: cx20442: don't use reg_cache

Codec reg_cache is legacy feature and very few driver only are using
it. But, ALSA SoC framework needs to support it.
Codec will be merged into Component in the future, so, let's remove
legacy and unused feature from framework.

cx20442 is using reg_cache but it is only 1byte, and it doesn't use
snd_soc_write/read/update_bits function which uses reg_cache.
reg_cache user is only debugfs. Let's clean reg_cache for now.
But let's keep .write function since it can be used for new additional
feature. .read will not be used, let's remove.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/cx20442.c

@@ -88,17 +88,6 @@ static const struct snd_soc_dapm_route cx20442_audio_map[] = {
 	{"ADC", NULL, "Input Mixer"},
 };
 
-static unsigned int cx20442_read_reg_cache(struct snd_soc_codec *codec,
-							unsigned int reg)
-{
-	u8 *reg_cache = codec->reg_cache;
-
-	if (reg >= codec->driver->reg_cache_size)
-		return -EINVAL;
-
-	return reg_cache[reg];
-}
-
 enum v253_vls {
 	V253_VLS_NONE = 0,
 	V253_VLS_T,
@@ -123,6 +112,8 @@ enum v253_vls {
 	V253_VLS_TEST,
 };
 
+#if 0
+/* FIXME : these function will be re-used */
 static int cx20442_pm_to_v253_vls(u8 value)
 {
 	switch (value & ~(1 << CX20442_AGC)) {
@@ -199,7 +190,7 @@ static int cx20442_write(struct snd_soc_codec *codec, unsigned int reg,
 
 	return 0;
 }
-
+#endif
 
 /*
  * Line discpline related code
@@ -399,11 +390,7 @@ static const struct snd_soc_codec_driver cx20442_codec_dev = {
 	.probe = 	cx20442_codec_probe,
 	.remove = 	cx20442_codec_remove,
 	.set_bias_level = cx20442_set_bias_level,
-	.reg_cache_default = &cx20442_reg,
-	.reg_cache_size = 1,
-	.reg_word_size = sizeof(u8),
-	.read = cx20442_read_reg_cache,
-	.write = cx20442_write,
+
 	.component_driver = {
 		.dapm_widgets		= cx20442_dapm_widgets,
 		.num_dapm_widgets	= ARRAY_SIZE(cx20442_dapm_widgets),