The magnetometer's power supply could be controlled by regulator
on some platforms, such as i.MX6Q-SABRESD board, the mag3110's
power supply is controlled by a GPIO fixed regulator, need to make
sure the regulator is enabled before any communication with mag3110,
this patch adds optional vdd/vddio regulator operation support.

Signed-off-by: Anson Huang <anson.hu...@nxp.com>
---
ChangeLog since V3:
        - add disabling vdd in vddio error path;
        - improve the regulator enable/disable sequence.
---
 drivers/iio/magnetometer/mag3110.c | 96 ++++++++++++++++++++++++++++++++++----
 1 file changed, 88 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/magnetometer/mag3110.c 
b/drivers/iio/magnetometer/mag3110.c
index f063355..328c0c4 100644
--- a/drivers/iio/magnetometer/mag3110.c
+++ b/drivers/iio/magnetometer/mag3110.c
@@ -20,6 +20,7 @@
 #include <linux/iio/buffer.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/delay.h>
+#include <linux/regulator/consumer.h>
 
 #define MAG3110_STATUS 0x00
 #define MAG3110_OUT_X 0x01 /* MSB first */
@@ -56,6 +57,8 @@ struct mag3110_data {
        struct mutex lock;
        u8 ctrl_reg1;
        int sleep_val;
+       struct regulator *vdd_reg;
+       struct regulator *vddio_reg;
 };
 
 static int mag3110_request(struct mag3110_data *data)
@@ -469,17 +472,46 @@ static int mag3110_probe(struct i2c_client *client,
        struct iio_dev *indio_dev;
        int ret;
 
-       ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
-       if (ret < 0)
-               return ret;
-       if (ret != MAG3110_DEVICE_ID)
-               return -ENODEV;
-
        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
        if (!indio_dev)
                return -ENOMEM;
 
        data = iio_priv(indio_dev);
+
+       data->vdd_reg = devm_regulator_get_optional(&client->dev, "vdd");
+       if (!IS_ERR(data->vdd_reg)) {
+               ret = regulator_enable(data->vdd_reg);
+               if (ret) {
+                       dev_err(&client->dev, "failed to enable VDD 
regulator\n");
+                       return ret;
+               }
+       } else {
+               ret = PTR_ERR(data->vdd_reg);
+               if (ret != -ENODEV)
+                       return ret;
+       }
+
+       data->vddio_reg = devm_regulator_get_optional(&client->dev, "vddio");
+       if (!IS_ERR(data->vddio_reg)) {
+               ret = regulator_enable(data->vddio_reg);
+               if (ret) {
+                       dev_err(&client->dev, "failed to enable VDDIO 
regulator\n");
+                       goto disable_regulator_vdd;
+               }
+       } else {
+               ret = PTR_ERR(data->vddio_reg);
+               if (ret != -ENODEV)
+                       goto disable_regulator_vdd;
+       }
+
+       ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
+       if (ret < 0)
+               goto disable_regulators;
+       if (ret != MAG3110_DEVICE_ID) {
+               ret = -ENODEV;
+               goto disable_regulators;
+       }
+
        data->client = client;
        mutex_init(&data->lock);
 
@@ -499,7 +531,7 @@ static int mag3110_probe(struct i2c_client *client,
 
        ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
        if (ret < 0)
-               return ret;
+               goto disable_regulators;
 
        ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
                MAG3110_CTRL_AUTO_MRST_EN);
@@ -520,6 +552,13 @@ static int mag3110_probe(struct i2c_client *client,
        iio_triggered_buffer_cleanup(indio_dev);
 standby_on_error:
        mag3110_standby(iio_priv(indio_dev));
+disable_regulators:
+       if (!IS_ERR(data->vddio_reg))
+               regulator_disable(data->vddio_reg);
+disable_regulator_vdd:
+       if (!IS_ERR(data->vdd_reg))
+               regulator_disable(data->vdd_reg);
+
        return ret;
 }
 
@@ -537,14 +576,55 @@ static int mag3110_remove(struct i2c_client *client)
 #ifdef CONFIG_PM_SLEEP
 static int mag3110_suspend(struct device *dev)
 {
-       return mag3110_standby(iio_priv(i2c_get_clientdata(
+       struct mag3110_data *data = iio_priv(i2c_get_clientdata(
+               to_i2c_client(dev)));
+       int ret;
+
+       ret = mag3110_standby(iio_priv(i2c_get_clientdata(
                to_i2c_client(dev))));
+       if (ret)
+               return ret;
+
+       if (!IS_ERR(data->vddio_reg)) {
+               ret = regulator_disable(data->vddio_reg);
+               if (ret) {
+                       dev_err(dev, "failed to disable VDDIO regulator\n");
+                       return ret;
+               }
+       }
+       if (!IS_ERR(data->vdd_reg)) {
+               ret = regulator_disable(data->vdd_reg);
+               if (ret) {
+                       dev_err(dev, "failed to disable VDD regulator\n");
+                       return ret;
+               }
+       }
+
+       return 0;
 }
 
 static int mag3110_resume(struct device *dev)
 {
        struct mag3110_data *data = iio_priv(i2c_get_clientdata(
                to_i2c_client(dev)));
+       int ret;
+
+       if (!IS_ERR(data->vdd_reg)) {
+               ret = regulator_enable(data->vdd_reg);
+               if (ret) {
+                       dev_err(dev, "failed to enable VDD regulator\n");
+                       return ret;
+               }
+       }
+       if (!IS_ERR(data->vddio_reg)) {
+               ret = regulator_enable(data->vddio_reg);
+               if (ret) {
+                       dev_err(dev, "failed to enable VDDIO regulator\n");
+                       if (!IS_ERR(data->vdd_reg))
+                               regulator_disable(data->vdd_reg);
+                       return ret;
+               }
+       }
 
        return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
                data->ctrl_reg1);
-- 
2.7.4

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