[alsa-devel] [PATCH v2] ASoC: rt5663: Delay and retry reading rt5663 ID register

[Oder Chiou]

In the probe, the codec may not be ready for I2C reading or there are some
glitches on the i2c line. So if the i2c reading value is incorrect, it will
read again after delay. This issue is similar the patch
https://patchwork.kernel.org/patch/9681421/. In current project, these 2
devices were connected to the same i2c line, and they met the same problem.

Signed-off-by: Oder Chiou <oder_chiou at realtek.com>
---
 sound/soc/codecs/rt5663.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/rt5663.c b/sound/soc/codecs/rt5663.c
index fcd1643..5985d8e 100644
--- a/sound/soc/codecs/rt5663.c
+++ b/sound/soc/codecs/rt5663.c
@@ -3429,7 +3429,16 @@ static int rt5663_i2c_probe(struct i2c_client *i2c,
 			ret);
 		return ret;
 	}
-	regmap_read(regmap, RT5663_VENDOR_ID_2, &val);
+
+	ret = regmap_read(regmap, RT5663_VENDOR_ID_2, &val);
+	if (ret || (val != RT5663_DEVICE_ID_2 && val != RT5663_DEVICE_ID_1)) {
+		dev_err(&i2c->dev,
+			"Device with ID register %#x is not rt5663,"
+			" retry one time.\n", val);
+		msleep(100);
+		regmap_read(regmap, RT5663_VENDOR_ID_2, &val);
+	}
+
 	switch (val) {
 	case RT5663_DEVICE_ID_2:
 		rt5663->regmap = devm_regmap_init_i2c(i2c, &rt5663_v2_regmap);
-- 
2.7.4