[1/2] 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>
---
 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h      |  3 ++
 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 42 ++++++++++++++++++++
 2 files changed, 45 insertions(+)

On Tue, 17 Nov 2020 16:11:37 +0100
Lorenzo Bianconi <lorenzo@kernel.org> wrote:

> 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>
Looks good to me.

> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h      |  3 ++
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c | 42 ++++++++++++++++++++
>  2 files changed, 45 insertions(+)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> index 1f31657a7a0e..4b4ec39d4400 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
> +++ b/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;
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> index da91f5e7e86d..8b9b724121a8 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c
> @@ -2549,6 +2549,40 @@ 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) {
> +		dev_err(dev, "failed to get regulators: %d\n", err);
> +		return err;
> +	}
> +
> +	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)
>  {
> @@ -2568,6 +2602,14 @@ 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;