ASoC: ssm4567: Reset device before regcache_sync()

[ Upstream commit 712a803 ] When the ssm4567 is powered up the driver calles regcache_sync() to restore the register map content. regcache_sync() assumes that the device is in its power-on reset state. Make sure that this is the case by explicitly resetting the ssm4567 register map before calling regcache_sync() otherwise we might end up with a incorrect register map which leads to undefined behaviour. One such undefined behaviour was observed when returning from system suspend while a playback stream is active, in that case the ssm4567 was kept muted after resume. Fixes: 1ee44ce ("ASoC: ssm4567: Add driver for Analog Devices SSM4567 amplifier") Reported-by: Harsha Priya <[email protected]> Tested-by: Fang, Yang A <[email protected]> Signed-off-by: Lars-Peter Clausen <[email protected]> Signed-off-by: Mark Brown <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
nemunaire · Jul 12, 2016 · 4253321 · 4253321
1 parent ad20c9b
commit 4253321
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/sound/soc/codecs/ssm4567.c b/sound/soc/codecs/ssm4567.c
@@ -206,6 +206,11 @@ static int ssm4567_set_power(struct ssm4567 *ssm4567, bool enable)
 	regcache_cache_only(ssm4567->regmap, !enable);
 
 	if (enable) {
+		ret = regmap_write(ssm4567->regmap, SSM4567_REG_SOFT_RESET,
+			0x00);
+		if (ret)
+			return ret;
+
 		ret = regmap_update_bits(ssm4567->regmap,
 			SSM4567_REG_POWER_CTRL,
 			SSM4567_POWER_SPWDN, 0x00);