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 vdd/vddio regulator operation support.

Signed-off-by: Anson Huang <anson.hu...@nxp.com>
Acked-by: Martin Kepplinger <mart...@posteo.de>
---
ChangeLog since V3:
        - add disabling vdd regulator in vddio error path;
        - improve regulator enable/disable sequence.
---
 drivers/iio/accel/mma8452.c | 186 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 176 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 421a0a8..590a95d 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 +108,8 @@ struct mma8452_data {
        u8 data_cfg;
        const struct mma_chip_info *chip_info;
        int sleep_val;
+       struct regulator *vdd_reg;
+       struct regulator *vddio_reg;
 };
 
  /**
@@ -1533,10 +1536,35 @@ static int mma8452_probe(struct i2c_client *client,
        data->client = client;
        mutex_init(&data->lock);
        data->chip_info = match->data;
+       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, MMA8452_WHO_AM_I);
        if (ret < 0)
-               return ret;
+               goto disable_regulators;
 
        switch (ret) {
        case MMA8451_DEVICE_ID:
@@ -1549,7 +1577,8 @@ static int mma8452_probe(struct i2c_client *client,
                        break;
                /* else: fall through */
        default:
-               return -ENODEV;
+               ret = -ENODEV;
+               goto disable_regulators;
        }
 
        dev_info(&client->dev, "registering %s accelerometer; ID 0x%x\n",
@@ -1566,13 +1595,13 @@ static int mma8452_probe(struct i2c_client *client,
 
        ret = mma8452_reset(client);
        if (ret < 0)
-               return ret;
+               goto disable_regulators;
 
        data->data_cfg = MMA8452_DATA_CFG_FS_2G;
        ret = i2c_smbus_write_byte_data(client, MMA8452_DATA_CFG,
                                        data->data_cfg);
        if (ret < 0)
-               return ret;
+               goto disable_regulators;
 
        /*
         * By default set transient threshold to max to avoid events if
@@ -1581,7 +1610,7 @@ static int mma8452_probe(struct i2c_client *client,
        ret = i2c_smbus_write_byte_data(client, MMA8452_TRANSIENT_THS,
                                        MMA8452_TRANSIENT_THS_MASK);
        if (ret < 0)
-               return ret;
+               goto disable_regulators;
 
        if (client->irq) {
                int irq2;
@@ -1595,7 +1624,7 @@ static int mma8452_probe(struct i2c_client *client,
                                                MMA8452_CTRL_REG5,
                                                data->chip_info->all_events);
                        if (ret < 0)
-                               return ret;
+                               goto disable_regulators;
 
                        dev_dbg(&client->dev, "using interrupt line INT1\n");
                }
@@ -1604,11 +1633,11 @@ static int mma8452_probe(struct i2c_client *client,
                                        MMA8452_CTRL_REG4,
                                        data->chip_info->enabled_events);
                if (ret < 0)
-                       return ret;
+                       goto disable_regulators;
 
                ret = mma8452_trigger_setup(indio_dev);
                if (ret < 0)
-                       return ret;
+                       goto disable_regulators;
        }
 
        data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
@@ -1661,12 +1690,22 @@ static int mma8452_probe(struct i2c_client *client,
 trigger_cleanup:
        mma8452_trigger_cleanup(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;
 }
 
 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 +1717,21 @@ static int mma8452_remove(struct i2c_client *client)
        mma8452_trigger_cleanup(indio_dev);
        mma8452_standby(iio_priv(indio_dev));
 
+       if (!IS_ERR(data->vddio_reg)) {
+               ret = regulator_disable(data->vddio_reg);
+               if (ret) {
+                       dev_err(&client->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(&client->dev, "failed to disable VDD 
regulator\n");
+                       return ret;
+               }
+       }
+
        return 0;
 }
 
@@ -1696,6 +1750,21 @@ static int mma8452_runtime_suspend(struct device *dev)
                return -EAGAIN;
        }
 
+       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;
 }
 
@@ -1705,6 +1774,23 @@ static int mma8452_runtime_resume(struct device *dev)
        struct mma8452_data *data = iio_priv(indio_dev);
        int ret, sleep_val;
 
+       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;
+               }
+       }
+
        ret = mma8452_active(data);
        if (ret < 0)
                return ret;
@@ -1723,14 +1809,94 @@ 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->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;
+               }
+       }
+
+       ret = mma8452_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 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->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;
+               }
+       }
+
+       ret = mma8452_active(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;
 }
 #endif
 
-- 
2.7.4

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