ASoC: rt5514: Unconfuse the rt5514 at probe / resume time

[mirror_ubuntu-bionic-kernel.git] / sound / soc / codecs / rt5514.c

diff --git a/sound/soc/codecs/rt5514.c b/sound/soc/codecs/rt5514.c
index 969a05620e04805faf0c17428027018862521141..f91221b1ddf0fced68a2815eaaf71f5983fea868 100644 (file)
--- a/sound/soc/codecs/rt5514.c
+++ b/sound/soc/codecs/rt5514.c
@@ -1084,6 +1084,21 @@ static int rt5514_parse_dt(struct rt5514_priv *rt5514, struct device *dev)
        return 0;
 }
 
+static __maybe_unused int rt5514_i2c_resume(struct device *dev)
+{
+       struct rt5514_priv *rt5514 = dev_get_drvdata(dev);
+       unsigned int val;
+
+       /*
+        * Add a bogus read to avoid rt5514's confusion after s2r in case it
+        * saw glitches on the i2c lines and thought the other side sent a
+        * start bit.
+        */
+       regmap_read(rt5514->regmap, RT5514_VENDOR_ID2, &val);
+
+       return 0;
+}
+
 static int rt5514_i2c_probe(struct i2c_client *i2c,
                    const struct i2c_device_id *id)
 {
@@ -1120,7 +1135,15 @@ static int rt5514_i2c_probe(struct i2c_client *i2c,
                return ret;
        }
 
+       /*
+        * The rt5514 can get confused if the i2c lines glitch together, as
+        * can happen at bootup as regulators are turned off and on.  If it's
+        * in this glitched state the first i2c read will fail, so we'll give
+        * it one change to retry.
+        */
        ret = regmap_read(rt5514->regmap, RT5514_VENDOR_ID2, &val);
+       if (ret || val != RT5514_DEVICE_ID)
+               ret = regmap_read(rt5514->regmap, RT5514_VENDOR_ID2, &val);
        if (ret || val != RT5514_DEVICE_ID) {
                dev_err(&i2c->dev,
                        "Device with ID register %x is not rt5514\n", val);
@@ -1149,10 +1172,15 @@ static int rt5514_i2c_remove(struct i2c_client *i2c)
        return 0;
 }
 
+static const struct dev_pm_ops rt5514_i2_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(NULL, rt5514_i2c_resume)
+};
+
 static struct i2c_driver rt5514_i2c_driver = {
        .driver = {
                .name = "rt5514",
                .of_match_table = of_match_ptr(rt5514_of_match),
+               .pm = &rt5514_i2_pm_ops,
        },
        .probe = rt5514_i2c_probe,
        .remove   = rt5514_i2c_remove,