[PATCH v4 1/2] ASoC: max98927: Handle reset gpio when probing i2c

[Alejandro Tafalla]

The max98927 codec on some devices requires pulling a reset gpio before
responding to any i2c command. This commit adds support for it through
an optional reset-gpios property.

Signed-off-by: Alejandro Tafalla <atafalla at dnyon.com>
---
 sound/soc/codecs/max98927.c | 25 +++++++++++++++++++++++++
 sound/soc/codecs/max98927.h |  1 +
 2 files changed, 26 insertions(+)

diff --git a/sound/soc/codecs/max98927.c b/sound/soc/codecs/max98927.c
index 8b206ee77709..5ba5f876eab8 100644
--- a/sound/soc/codecs/max98927.c
+++ b/sound/soc/codecs/max98927.c
@@ -897,6 +897,19 @@ static int max98927_i2c_probe(struct i2c_client *i2c,
 			"Failed to allocate regmap: %d\n", ret);
 		return ret;
 	}
+	
+	max98927->reset_gpio 
+		= devm_gpiod_get_optional(&i2c->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(max98927->reset_gpio)) {
+		ret = PTR_ERR(max98927->reset_gpio);
+		return dev_err_probe(&i2c->dev, ret, "failed to request GPIO reset pin");
+	}
+
+	if (max98927->reset_gpio) {
+		gpiod_set_value_cansleep(max98927->reset_gpio, 0);
+		/* Wait for i2c port to be ready */
+		usleep_range(5000, 6000);
+	}
 
 	/* Check Revision ID */
 	ret = regmap_read(max98927->regmap,
@@ -921,6 +934,17 @@ static int max98927_i2c_probe(struct i2c_client *i2c,
 	return ret;
 }
 
+static int max98927_i2c_remove(struct i2c_client *i2c)
+{
+	struct max98927_priv *max98927 = i2c_get_clientdata(i2c);
+
+	if (max98927->reset_gpio) {
+		gpiod_set_value_cansleep(max98927->reset_gpio, 1);
+	}
+
+	return 0;
+}
+
 static const struct i2c_device_id max98927_i2c_id[] = {
 	{ "max98927", 0},
 	{ },
@@ -952,6 +976,7 @@ static struct i2c_driver max98927_i2c_driver = {
 		.pm = &max98927_pm,
 	},
 	.probe  = max98927_i2c_probe,
+	.remove = max98927_i2c_remove,
 	.id_table = max98927_i2c_id,
 };
 
diff --git a/sound/soc/codecs/max98927.h b/sound/soc/codecs/max98927.h
index 05f495db914d..13f5066d7419 100644
--- a/sound/soc/codecs/max98927.h
+++ b/sound/soc/codecs/max98927.h
@@ -255,6 +255,7 @@ struct max98927_priv {
 	struct regmap *regmap;
 	struct snd_soc_component *component;
 	struct max98927_pdata *pdata;
+	struct gpio_desc *reset_gpio; 
 	unsigned int spk_gain;
 	unsigned int sysclk;
 	unsigned int v_l_slot;
-- 
2.33.0