[PATCH 2/2] ASoC: rt5682: fix getting the wrong device id when the suspend_stress_test

[shumingf at realtek.com]

From: Shuming Fan <shumingf at realtek.com>

This patch will be the workaround to fix getting the wrong device ID on the rare chance.
It seems like something unstable when the system resumes. e.g. the bus clock
This patch tries to read the device ID to check several times.
After the test, the driver will get the correct device ID the second time.

Signed-off-by: Shuming Fan <shumingf at realtek.com>
---
 sound/soc/codecs/rt5682-sdw.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/sound/soc/codecs/rt5682-sdw.c b/sound/soc/codecs/rt5682-sdw.c
index 4d707e854875..69f046bba67a 100644
--- a/sound/soc/codecs/rt5682-sdw.c
+++ b/sound/soc/codecs/rt5682-sdw.c
@@ -375,18 +375,12 @@ static int rt5682_sdw_init(struct device *dev, struct regmap *regmap,
 static int rt5682_io_init(struct device *dev, struct sdw_slave *slave)
 {
 	struct rt5682_priv *rt5682 = dev_get_drvdata(dev);
-	int ret = 0;
+	int ret = 0, loop = 10;
 	unsigned int val;
 
 	if (rt5682->hw_init)
 		return 0;
 
-	regmap_read(rt5682->regmap, RT5682_DEVICE_ID, &val);
-	if (val != DEVICE_ID) {
-		dev_err(dev, "Device with ID register %x is not rt5682\n", val);
-		return -ENODEV;
-	}
-
 	/*
 	 * PM runtime is only enabled when a Slave reports as Attached
 	 */
@@ -406,6 +400,19 @@ static int rt5682_io_init(struct device *dev, struct sdw_slave *slave)
 
 	pm_runtime_get_noresume(&slave->dev);
 
+	while (loop > 0) {
+		regmap_read(rt5682->regmap, RT5682_DEVICE_ID, &val);
+		if (val == DEVICE_ID)
+			break;
+		dev_warn(dev, "Device with ID register %x is not rt5682\n", val);
+		usleep_range(30000, 30005);
+		loop--;
+	}
+	if (val != DEVICE_ID) {
+		dev_err(dev, "Device with ID register %x is not rt5682\n", val);
+		return -ENODEV;
+	}
+
 	if (rt5682->first_hw_init) {
 		regcache_cache_only(rt5682->regmap, false);
 		regcache_cache_bypass(rt5682->regmap, true);
-- 
2.29.0