ASoC: tlv320aic3x: Mark the RESET register as volatile

BugLink: http://bugs.launchpad.net/bugs/1710646

[ Upstream commit 63c3194b ]

The RESET register only have one self clearing bit and it should not be
cached. If it is cached, when we sync the registers back to the chip we
will initiate a software reset as well, which is not desirable.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Reviewed-by: Jarkko Nikula <jarkko.nikula@bitmer.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

sound/soc/codecs/tlv320aic3x.c

@@ -126,6 +126,16 @@ static const struct reg_default aic3x_reg[] = {
 	{ 108, 0x00 }, { 109, 0x00 },
 };
 
+static bool aic3x_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case AIC3X_RESET:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static const struct regmap_config aic3x_regmap = {
 	.reg_bits = 8,
 	.val_bits = 8,
@@ -133,6 +143,9 @@ static const struct regmap_config aic3x_regmap = {
 	.max_register = DAC_ICC_ADJ,
 	.reg_defaults = aic3x_reg,
 	.num_reg_defaults = ARRAY_SIZE(aic3x_reg),
+
+	.volatile_reg = aic3x_volatile_reg,
+
 	.cache_type = REGCACHE_RBTREE,
 };