[PATCH V6 2/2] iio: accell: mma8452: add vdd/vddio regulator operation support

[Anson Huang]

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

Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
Acked-by: Martin Kepplinger <martink@xxxxxxxxx>
---
ChangeLog since V5:
    - ONLY enable vdd/vddio regulators after both of them are aquired;
    - Since the suspend/resume operations are same as runtime suspend/resume, so just use the
      pm_runtime_force_suspend/resume for suspend/resuem callback to simply the code.
---
 drivers/iio/accel/mma8452.c | 99 +++++++++++++++++++++++++++++++++++----------
 1 file changed, 77 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 421a0a8..7519ed5 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;
 };
 
  /**
@@ -1534,9 +1537,33 @@ static int mma8452_probe(struct i2c_client *client,
 	mutex_init(&data->lock);
 	data->chip_info = match->data;
 
+	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
+	data->vddio_reg = devm_regulator_get(&client->dev, "vddio");
+	if (IS_ERR(data->vdd_reg) || IS_ERR(data->vddio_reg)) {
+		if (PTR_ERR(data->vdd_reg) == -EPROBE_DEFER ||
+			PTR_ERR(data->vddio_reg) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		dev_err(&client->dev, "failed to get VDD/VDDIO regulator!\n");
+		return IS_ERR(data->vdd_reg) ?
+		       PTR_ERR(data->vdd_reg) : PTR_ERR(data->vddio_reg);
+	}
+
+	ret = regulator_enable(data->vdd_reg);
+	if (ret) {
+		dev_err(&client->dev, "failed to enable VDD regulator!\n");
+		return ret;
+	}
+
+	ret = regulator_enable(data->vddio_reg);
+	if (ret) {
+		dev_err(&client->dev, "failed to enable VDDIO regulator!\n");
+		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 +1576,8 @@ 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 +1594,13 @@ 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 +1609,7 @@ 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 +1623,7 @@ 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 +1632,11 @@ 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 +1689,19 @@ static int mma8452_probe(struct i2c_client *client,
 trigger_cleanup:
 	mma8452_trigger_cleanup(indio_dev);
 
+disable_regulators:
+	regulator_disable(data->vddio_reg);
+
+disable_regulator_vdd:
+	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);
 
 	iio_device_unregister(indio_dev);
 
@@ -1678,6 +1713,9 @@ static int mma8452_remove(struct i2c_client *client)
 	mma8452_trigger_cleanup(indio_dev);
 	mma8452_standby(iio_priv(indio_dev));
 
+	regulator_disable(data->vddio_reg);
+	regulator_disable(data->vdd_reg);
+
 	return 0;
 }
 
@@ -1696,6 +1734,18 @@ static int mma8452_runtime_suspend(struct device *dev)
 		return -EAGAIN;
 	}
 
+	ret = regulator_disable(data->vddio_reg);
+	if (ret) {
+		dev_err(dev, "failed to disable VDDIO regulator\n");
+		return ret;
+	}
+
+	ret = regulator_disable(data->vdd_reg);
+	if (ret) {
+		dev_err(dev, "failed to disable VDD regulator\n");
+		return ret;
+	}
+
 	return 0;
 }
 
@@ -1705,9 +1755,22 @@ static int mma8452_runtime_resume(struct device *dev)
 	struct mma8452_data *data = iio_priv(indio_dev);
 	int ret, sleep_val;
 
+	ret = regulator_enable(data->vdd_reg);
+	if (ret) {
+		dev_err(dev, "failed to enable VDD regulator\n");
+		return ret;
+	}
+
+	ret = regulator_enable(data->vddio_reg);
+	if (ret) {
+		dev_err(dev, "failed to enable VDDIO regulator\n");
+		regulator_disable(data->vdd_reg);
+		return ret;
+	}
+
 	ret = mma8452_active(data);
 	if (ret < 0)
-		return ret;
+		goto runtime_resume_failed;
 
 	ret = mma8452_get_odr_index(data);
 	sleep_val = 1000 / mma8452_samp_freq[ret][0];
@@ -1717,25 +1780,17 @@ static int mma8452_runtime_resume(struct device *dev)
 		msleep_interruptible(sleep_val);
 
 	return 0;
-}
-#endif
 
-#ifdef CONFIG_PM_SLEEP
-static int mma8452_suspend(struct device *dev)
-{
-	return mma8452_standby(iio_priv(i2c_get_clientdata(
-		to_i2c_client(dev))));
-}
+runtime_resume_failed:
+	regulator_disable(data->vddio_reg);
+	regulator_disable(data->vdd_reg);
 
-static int mma8452_resume(struct device *dev)
-{
-	return mma8452_active(iio_priv(i2c_get_clientdata(
-		to_i2c_client(dev))));
+	return ret;
 }
 #endif
 
 static const struct dev_pm_ops mma8452_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(mma8452_suspend, mma8452_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
 	SET_RUNTIME_PM_OPS(mma8452_runtime_suspend,
 			   mma8452_runtime_resume, NULL)
 };
-- 
2.7.4