iio: imu: st_lsm6dsx: add vdd-vddio voltage regulator

Like all other ST sensors, st_lsm6dsx devices have VDD and VDDIO power
lines. Introduce voltage regulators to control them.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/a0427a66360bdec73c3b1fb536a46240f96b2ae7.1605631305.git.lorenzo@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h

@@ -13,6 +13,7 @@
 
 #include <linux/device.h>
 #include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
 
 #define ST_LSM6DS3_DEV_NAME	"lsm6ds3"
 #define ST_LSM6DS3H_DEV_NAME	"lsm6ds3h"
@@ -368,6 +369,7 @@ struct st_lsm6dsx_sensor {
  * struct st_lsm6dsx_hw - ST IMU MEMS hw instance
  * @dev: Pointer to instance of struct device (I2C or SPI).
  * @regmap: Register map of the device.
+ * @regulators: VDD/VDDIO voltage regulators.
  * @irq: Device interrupt line (I2C or SPI).
  * @fifo_lock: Mutex to prevent concurrent access to the hw FIFO.
  * @conf_lock: Mutex to prevent concurrent FIFO configuration update.
@@ -390,6 +392,7 @@ struct st_lsm6dsx_sensor {
 struct st_lsm6dsx_hw {
 	struct device *dev;
 	struct regmap *regmap;
+	struct regulator_bulk_data regulators[2];
 	int irq;
 
 	struct mutex fifo_lock;

drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c

@@ -2533,6 +2533,38 @@ static int st_lsm6dsx_irq_setup(struct st_lsm6dsx_hw *hw)
 	return 0;
 }
 
+static int st_lsm6dsx_init_regulators(struct device *dev)
+{
+	struct st_lsm6dsx_hw *hw = dev_get_drvdata(dev);
+	int err;
+
+	/* vdd-vddio power regulators */
+	hw->regulators[0].supply = "vdd";
+	hw->regulators[1].supply = "vddio";
+	err = devm_regulator_bulk_get(dev, ARRAY_SIZE(hw->regulators),
+				      hw->regulators);
+	if (err)
+		return dev_err_probe(dev, err, "failed to get regulators\n");
+
+	err = regulator_bulk_enable(ARRAY_SIZE(hw->regulators),
+				    hw->regulators);
+	if (err) {
+		dev_err(dev, "failed to enable regulators: %d\n", err);
+		return err;
+	}
+
+	msleep(50);
+
+	return 0;
+}
+
+static void st_lsm6dsx_chip_uninit(void *data)
+{
+	struct st_lsm6dsx_hw *hw = data;
+
+	regulator_bulk_disable(ARRAY_SIZE(hw->regulators), hw->regulators);
+}
+
 int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id,
 		     struct regmap *regmap)
 {
@@ -2552,6 +2584,14 @@ int st_lsm6dsx_probe(struct device *dev, int irq, int hw_id,
 	mutex_init(&hw->conf_lock);
 	mutex_init(&hw->page_lock);
 
+	err = st_lsm6dsx_init_regulators(dev);
+	if (err)
+		return err;
+
+	err = devm_add_action_or_reset(dev, st_lsm6dsx_chip_uninit, hw);
+	if (err)
+		return err;
+
 	hw->buff = devm_kzalloc(dev, ST_LSM6DSX_BUFF_SIZE, GFP_KERNEL);
 	if (!hw->buff)
 		return -ENOMEM;