[PATCH] ASoC: rt715: Add module parameter to fix dmic pop sound issue.

[Pierre-Louis Bossart]

From: Jack Yu <jack.yu at realtek.com>

Add module parameter "power_up_delay" to fix pop noise on capture. The
power_up_delay value is set with a default value of 400ms, smaller
values are not recommended.

BugLink: https://github.com/thesofproject/linux/issues/1969
Reviewed-by: Bard Liao <yung-chuan.liao at linux.intel.com>
Reviewed-by: Rander Wang <rander.wang at linux.intel.com>
Signed-off-by: Jack Yu <jack.yu at realtek.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 sound/soc/codecs/rt715.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sound/soc/codecs/rt715.c b/sound/soc/codecs/rt715.c
index 099c8bd20006..0cf10dec1e3b 100644
--- a/sound/soc/codecs/rt715.c
+++ b/sound/soc/codecs/rt715.c
@@ -37,6 +37,10 @@
 
 #include "rt715.h"
 
+static int power_up_delay = 400;
+module_param(power_up_delay, int, 0444);
+MODULE_PARM_DESC(power_up_delay, "RT715 power up delay time in ms");
+
 static int rt715_index_write(struct regmap *regmap, unsigned int reg,
 		unsigned int value)
 {
@@ -498,6 +502,7 @@ static int rt715_set_bias_level(struct snd_soc_component *component,
 			regmap_write(rt715->regmap,
 						RT715_SET_AUDIO_POWER_STATE,
 						AC_PWRST_D0);
+			msleep(power_up_delay);
 		}
 		break;
 
-- 
2.25.1