[PATCH 5.10 020/103] ASoC: max98373: Changed amp shutdown register as volatile

[Greg Kroah-Hartman]

From: Ryan Lee <ryans.lee@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit a23f9099ff1541f15704e96b784d3846d2a4483d ]

0x20FF(amp global enable) register was defined as non-volatile,
but it is not. Overheating, overcurrent can cause amp shutdown
in hardware.
'regmap_write' compare register readback value before writing
to avoid same value writing. 'regmap_read' just read cache
not actual hardware value for the non-volatile register.
When amp is internally shutdown by some reason, next 'AMP ON'
command can be ignored because regmap think amp is already ON.

Signed-off-by: Ryan Lee <ryans.lee@xxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210325033555.29377-1-ryans.lee@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 sound/soc/codecs/max98373-i2c.c | 1 +
 sound/soc/codecs/max98373-sdw.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/sound/soc/codecs/max98373-i2c.c b/sound/soc/codecs/max98373-i2c.c
index 92921e34f948..32b0c1d98365 100644
--- a/sound/soc/codecs/max98373-i2c.c
+++ b/sound/soc/codecs/max98373-i2c.c
@@ -440,6 +440,7 @@ static bool max98373_volatile_reg(struct device *dev, unsigned int reg)
 	case MAX98373_R2054_MEAS_ADC_PVDD_CH_READBACK:
 	case MAX98373_R2055_MEAS_ADC_THERM_CH_READBACK:
 	case MAX98373_R20B6_BDE_CUR_STATE_READBACK:
+	case MAX98373_R20FF_GLOBAL_SHDN:
 	case MAX98373_R21FF_REV_ID:
 		return true;
 	default:
diff --git a/sound/soc/codecs/max98373-sdw.c b/sound/soc/codecs/max98373-sdw.c
index fa589d834f9a..14fd2f9a0bf3 100644
--- a/sound/soc/codecs/max98373-sdw.c
+++ b/sound/soc/codecs/max98373-sdw.c
@@ -214,6 +214,7 @@ static bool max98373_volatile_reg(struct device *dev, unsigned int reg)
 	case MAX98373_R2054_MEAS_ADC_PVDD_CH_READBACK:
 	case MAX98373_R2055_MEAS_ADC_THERM_CH_READBACK:
 	case MAX98373_R20B6_BDE_CUR_STATE_READBACK:
+	case MAX98373_R20FF_GLOBAL_SHDN:
 	case MAX98373_R21FF_REV_ID:
 	/* SoundWire Control Port Registers */
 	case MAX98373_R0040_SCP_INIT_STAT_1 ... MAX98373_R0070_SCP_FRAME_CTLR:
-- 
2.30.2