[PATCH 2/3] ASoC: codecs: rt5640: Retry DEVICE_ID verification

[Cezary Rojewski <cezary.rojewski@intel.com>]

From: Xinxin Wan <xinxin.wan@intel.com>

To be more resilient to codec-detection failures when the hardware
powers on slowly, add retry mechanism to the device verification check.
Similar pattern is found throughout a number of Realtek codecs. Our
tests show that 60ms delay is sufficient to address readiness issues on
rt5640 chip.

Reviewed-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Xinxin Wan <xinxin.wan@intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
---
 sound/soc/codecs/rt5640.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sound/soc/codecs/rt5640.c b/sound/soc/codecs/rt5640.c
index 265b30856faf..f50e771db24b 100644
--- a/sound/soc/codecs/rt5640.c
+++ b/sound/soc/codecs/rt5640.c
@@ -3013,6 +3013,11 @@ static int rt5640_i2c_probe(struct i2c_client *i2c)
 	}
 
 	regmap_read(rt5640->regmap, RT5640_VENDOR_ID2, &val);
+	if (val != RT5640_DEVICE_ID) {
+		usleep_range(60000, 100000);
+		regmap_read(rt5640->regmap, RT5640_VENDOR_ID2, &val);
+	}
+
 	if (val != RT5640_DEVICE_ID) {
 		dev_err(&i2c->dev,
 			"Device with ID register %#x is not rt5640/39\n", val);
-- 
2.25.1