[PATCH 2/2] iio: accell: mma8452: add optional vcc regulator operation support

[Anson Huang <anson.huang@xxxxxxx>]

The accelerometer's power supply could be controlled by regulator
on some platforms, such as i.MX6Q-SABRESD board, the mma8451's
power supply is controlled by a GPIO fixed regulator, need to make
sure the regulator is enabled before any communication with mma8451,
this patch adds optional vcc regulator operation support.

Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
---
 drivers/iio/accel/mma8452.c | 88 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 86 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 421a0a8..8f6123f 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -31,6 +31,7 @@
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
 #include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
 
 #define MMA8452_STATUS				0x00
 #define  MMA8452_STATUS_DRDY			(BIT(2) | BIT(1) | BIT(0))
@@ -107,6 +108,7 @@ struct mma8452_data {
 	u8 data_cfg;
 	const struct mma_chip_info *chip_info;
 	int sleep_val;
+	struct regulator *vcc_reg;
 };
 
  /**
@@ -1533,6 +1535,14 @@ static int mma8452_probe(struct i2c_client *client,
 	data->client = client;
 	mutex_init(&data->lock);
 	data->chip_info = match->data;
+	data->vcc_reg = devm_regulator_get_optional(&client->dev, "vcc");
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_enable(data->vcc_reg);
+		if (ret) {
+			dev_err(&client->dev, "failed to enable VCC regulator\n");
+			return ret;
+		}
+	}
 
 	ret = i2c_smbus_read_byte_data(client, MMA8452_WHO_AM_I);
 	if (ret < 0)
@@ -1667,6 +1677,8 @@ static int mma8452_probe(struct i2c_client *client,
 static int mma8452_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct mma8452_data *data = iio_priv(indio_dev);
+	int ret;
 
 	iio_device_unregister(indio_dev);
 
@@ -1678,6 +1690,14 @@ static int mma8452_remove(struct i2c_client *client)
 	mma8452_trigger_cleanup(indio_dev);
 	mma8452_standby(iio_priv(indio_dev));
 
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_disable(data->vcc_reg);
+		if (ret) {
+			dev_err(&client->dev, "failed to disable VCC regulator\n");
+			return ret;
+		}
+	}
+
 	return 0;
 }
 
@@ -1696,6 +1716,14 @@ static int mma8452_runtime_suspend(struct device *dev)
 		return -EAGAIN;
 	}
 
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_disable(data->vcc_reg);
+		if (ret) {
+			dev_err(dev, "failed to disable VCC regulator\n");
+			return ret;
+		}
+	}
+
 	return 0;
 }
 
@@ -1705,6 +1733,14 @@ static int mma8452_runtime_resume(struct device *dev)
 	struct mma8452_data *data = iio_priv(indio_dev);
 	int ret, sleep_val;
 
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_enable(data->vcc_reg);
+		if (ret) {
+			dev_err(dev, "failed to enable VCC regulator\n");
+			return ret;
+		}
+	}
+
 	ret = mma8452_active(data);
 	if (ret < 0)
 		return ret;
@@ -1723,14 +1759,62 @@ static int mma8452_runtime_resume(struct device *dev)
 #ifdef CONFIG_PM_SLEEP
 static int mma8452_suspend(struct device *dev)
 {
-	return mma8452_standby(iio_priv(i2c_get_clientdata(
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct mma8452_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_enable(data->vcc_reg);
+		if (ret) {
+			dev_err(dev, "failed to enable VCC regulator\n");
+			return ret;
+		}
+	}
+
+	ret = mma8452_standby(iio_priv(i2c_get_clientdata(
 		to_i2c_client(dev))));
+	if (ret)
+		return ret;
+
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_disable(data->vcc_reg);
+		if (ret) {
+			dev_err(dev, "failed to disable VCC regulator\n");
+			return ret;
+		}
+	}
+
+	return 0;
 }
 
 static int mma8452_resume(struct device *dev)
 {
-	return mma8452_active(iio_priv(i2c_get_clientdata(
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct mma8452_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_enable(data->vcc_reg);
+		if (ret) {
+			dev_err(dev, "failed to enable VCC regulator\n");
+			return ret;
+		}
+	}
+
+	ret = mma8452_active(iio_priv(i2c_get_clientdata(
 		to_i2c_client(dev))));
+	if (ret)
+		return ret;
+
+	if (!IS_ERR(data->vcc_reg)) {
+		ret = regulator_disable(data->vcc_reg);
+		if (ret) {
+			dev_err(dev, "failed to disable VCC regulator\n");
+			return ret;
+		}
+	}
+
+	return 0;
 }
 #endif
 
-- 
2.7.4