Re: [PATCH 2/4] iio: st_sensors: remove st_sensors_power_disable() function

[Jonathan Cameron]

On Mon, 26 Jul 2021 10:14:02 +0300
Alexandru Ardelean <aardelean@xxxxxxxxxxx> wrote:

> This change converts the st_sensors_power_enable() function to use
> devm_add_action_or_reset() handlers to register regulator_disable hooks for
> when the drivers get unloaded.
> 
> The parent device of the IIO device object is used. This is based on the
> assumption that all other devm_ calls in the ST sensors use this reference.
> 
> This makes the st_sensors_power_disable() un-needed.
> Removing this also changes unload order a bit, as all ST drivers would call
> st_sensors_power_disable() first and iio_device_unregister() after that.

Huh.  So currently the drivers turn the power off before calling
iio_device_unregister()?

That's a bad idea (turn off power when userspace is still available)
and looks like a bug fix to me.  Perhaps the reorder should be pulled out as
a precursor patch in case anyone wants to backport it?

(note I initially thought you were going the other way and was just writing
 a rant about breaking the order when I realised you were fixing it ;)

> 
> Signed-off-by: Alexandru Ardelean <aardelean@xxxxxxxxxxx>
> ---
>  drivers/iio/accel/st_accel_i2c.c              | 13 +------
>  drivers/iio/accel/st_accel_spi.c              | 13 +------
>  .../iio/common/st_sensors/st_sensors_core.c   | 34 ++++++++-----------
>  drivers/iio/gyro/st_gyro_i2c.c                | 13 +------
>  drivers/iio/gyro/st_gyro_spi.c                | 13 +------
>  drivers/iio/magnetometer/st_magn_i2c.c        | 13 +------
>  drivers/iio/magnetometer/st_magn_spi.c        | 13 +------
>  drivers/iio/pressure/st_pressure_i2c.c        | 13 +------
>  drivers/iio/pressure/st_pressure_spi.c        | 13 +------
>  include/linux/iio/common/st_sensors.h         |  2 --
>  10 files changed, 23 insertions(+), 117 deletions(-)
> 
> diff --git a/drivers/iio/accel/st_accel_i2c.c b/drivers/iio/accel/st_accel_i2c.c
> index f711756e41e3..b377575efc41 100644
> --- a/drivers/iio/accel/st_accel_i2c.c
> +++ b/drivers/iio/accel/st_accel_i2c.c
> @@ -177,24 +177,13 @@ static int st_accel_i2c_probe(struct i2c_client *client)
>  	if (ret)
>  		return ret;
>  
> -	ret = st_accel_common_probe(indio_dev);
> -	if (ret < 0)
> -		goto st_accel_power_off;
> -
> -	return 0;
> -
> -st_accel_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return ret;
> +	return st_accel_common_probe(indio_dev);
>  }
>  
>  static int st_accel_i2c_remove(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_accel_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/iio/accel/st_accel_spi.c b/drivers/iio/accel/st_accel_spi.c
> index bb45d9ff95b8..4ca87e73bdb3 100644
> --- a/drivers/iio/accel/st_accel_spi.c
> +++ b/drivers/iio/accel/st_accel_spi.c
> @@ -127,24 +127,13 @@ static int st_accel_spi_probe(struct spi_device *spi)
>  	if (err)
>  		return err;
>  
> -	err = st_accel_common_probe(indio_dev);
> -	if (err < 0)
> -		goto st_accel_power_off;
> -
> -	return 0;
> -
> -st_accel_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return err;
> +	return st_accel_common_probe(indio_dev);
>  }
>  
>  static int st_accel_spi_remove(struct spi_device *spi)
>  {
>  	struct iio_dev *indio_dev = spi_get_drvdata(spi);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_accel_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
> index 0bbb090b108c..a5a140de9a23 100644
> --- a/drivers/iio/common/st_sensors/st_sensors_core.c
> +++ b/drivers/iio/common/st_sensors/st_sensors_core.c
> @@ -215,13 +215,19 @@ int st_sensors_set_axis_enable(struct iio_dev *indio_dev, u8 axis_enable)
>  }
>  EXPORT_SYMBOL(st_sensors_set_axis_enable);
>  
> +static void st_reg_disable(void *reg)
> +{
> +	regulator_disable(reg);
> +}
> +
>  int st_sensors_power_enable(struct iio_dev *indio_dev)
>  {
>  	struct st_sensor_data *pdata = iio_priv(indio_dev);
> +	struct device *parent = indio_dev->dev.parent;
>  	int err;
>  
>  	/* Regulators not mandatory, but if requested we should enable them. */
> -	pdata->vdd = devm_regulator_get(indio_dev->dev.parent, "vdd");
> +	pdata->vdd = devm_regulator_get(parent, "vdd");
>  	if (IS_ERR(pdata->vdd)) {
>  		dev_err(&indio_dev->dev, "unable to get Vdd supply\n");
>  		return PTR_ERR(pdata->vdd);
> @@ -233,36 +239,26 @@ int st_sensors_power_enable(struct iio_dev *indio_dev)
>  		return err;
>  	}
>  
> -	pdata->vdd_io = devm_regulator_get(indio_dev->dev.parent, "vddio");
> +	err = devm_add_action_or_reset(parent, st_reg_disable, pdata->vdd);
> +	if (err)
> +		return err;
> +
> +	pdata->vdd_io = devm_regulator_get(parent, "vddio");
>  	if (IS_ERR(pdata->vdd_io)) {
>  		dev_err(&indio_dev->dev, "unable to get Vdd_IO supply\n");
> -		err = PTR_ERR(pdata->vdd_io);
> -		goto st_sensors_disable_vdd;
> +		return PTR_ERR(pdata->vdd_io);
>  	}
>  	err = regulator_enable(pdata->vdd_io);
>  	if (err != 0) {
>  		dev_warn(&indio_dev->dev,
>  			 "Failed to enable specified Vdd_IO supply\n");
> -		goto st_sensors_disable_vdd;
> +		return err;
>  	}
>  
> -	return 0;
> -
> -st_sensors_disable_vdd:
> -	regulator_disable(pdata->vdd);
> -	return err;
> +	return devm_add_action_or_reset(parent, st_reg_disable, pdata->vdd_io);
>  }
>  EXPORT_SYMBOL(st_sensors_power_enable);
>  
> -void st_sensors_power_disable(struct iio_dev *indio_dev)
> -{
> -	struct st_sensor_data *pdata = iio_priv(indio_dev);
> -
> -	regulator_disable(pdata->vdd);
> -	regulator_disable(pdata->vdd_io);
> -}
> -EXPORT_SYMBOL(st_sensors_power_disable);
> -
>  static int st_sensors_set_drdy_int_pin(struct iio_dev *indio_dev,
>  					struct st_sensors_platform_data *pdata)
>  {
> diff --git a/drivers/iio/gyro/st_gyro_i2c.c b/drivers/iio/gyro/st_gyro_i2c.c
> index 3ef86e16ee65..0bd80dfd389f 100644
> --- a/drivers/iio/gyro/st_gyro_i2c.c
> +++ b/drivers/iio/gyro/st_gyro_i2c.c
> @@ -90,24 +90,13 @@ static int st_gyro_i2c_probe(struct i2c_client *client,
>  	if (err)
>  		return err;
>  
> -	err = st_gyro_common_probe(indio_dev);
> -	if (err < 0)
> -		goto st_gyro_power_off;
> -
> -	return 0;
> -
> -st_gyro_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return err;
> +	return st_gyro_common_probe(indio_dev);
>  }
>  
>  static int st_gyro_i2c_remove(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_gyro_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/iio/gyro/st_gyro_spi.c b/drivers/iio/gyro/st_gyro_spi.c
> index 41d835493347..f74b09fa5cde 100644
> --- a/drivers/iio/gyro/st_gyro_spi.c
> +++ b/drivers/iio/gyro/st_gyro_spi.c
> @@ -94,24 +94,13 @@ static int st_gyro_spi_probe(struct spi_device *spi)
>  	if (err)
>  		return err;
>  
> -	err = st_gyro_common_probe(indio_dev);
> -	if (err < 0)
> -		goto st_gyro_power_off;
> -
> -	return 0;
> -
> -st_gyro_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return err;
> +	return st_gyro_common_probe(indio_dev);
>  }
>  
>  static int st_gyro_spi_remove(struct spi_device *spi)
>  {
>  	struct iio_dev *indio_dev = spi_get_drvdata(spi);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_gyro_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/iio/magnetometer/st_magn_i2c.c b/drivers/iio/magnetometer/st_magn_i2c.c
> index 2dfe4ee99591..0a5117dffcf4 100644
> --- a/drivers/iio/magnetometer/st_magn_i2c.c
> +++ b/drivers/iio/magnetometer/st_magn_i2c.c
> @@ -86,24 +86,13 @@ static int st_magn_i2c_probe(struct i2c_client *client,
>  	if (err)
>  		return err;
>  
> -	err = st_magn_common_probe(indio_dev);
> -	if (err < 0)
> -		goto st_magn_power_off;
> -
> -	return 0;
> -
> -st_magn_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return err;
> +	return st_magn_common_probe(indio_dev);
>  }
>  
>  static int st_magn_i2c_remove(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_magn_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/iio/magnetometer/st_magn_spi.c b/drivers/iio/magnetometer/st_magn_spi.c
> index fba978796395..1f3bf02b24e0 100644
> --- a/drivers/iio/magnetometer/st_magn_spi.c
> +++ b/drivers/iio/magnetometer/st_magn_spi.c
> @@ -80,24 +80,13 @@ static int st_magn_spi_probe(struct spi_device *spi)
>  	if (err)
>  		return err;
>  
> -	err = st_magn_common_probe(indio_dev);
> -	if (err < 0)
> -		goto st_magn_power_off;
> -
> -	return 0;
> -
> -st_magn_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return err;
> +	return st_magn_common_probe(indio_dev);
>  }
>  
>  static int st_magn_spi_remove(struct spi_device *spi)
>  {
>  	struct iio_dev *indio_dev = spi_get_drvdata(spi);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_magn_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/iio/pressure/st_pressure_i2c.c b/drivers/iio/pressure/st_pressure_i2c.c
> index 52fa98f24478..afeeab485c0d 100644
> --- a/drivers/iio/pressure/st_pressure_i2c.c
> +++ b/drivers/iio/pressure/st_pressure_i2c.c
> @@ -103,24 +103,13 @@ static int st_press_i2c_probe(struct i2c_client *client,
>  	if (ret)
>  		return ret;
>  
> -	ret = st_press_common_probe(indio_dev);
> -	if (ret < 0)
> -		goto st_press_power_off;
> -
> -	return 0;
> -
> -st_press_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return ret;
> +	return st_press_common_probe(indio_dev);
>  }
>  
>  static int st_press_i2c_remove(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_press_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/drivers/iio/pressure/st_pressure_spi.c b/drivers/iio/pressure/st_pressure_spi.c
> index ee393df54cee..834ad6d40a70 100644
> --- a/drivers/iio/pressure/st_pressure_spi.c
> +++ b/drivers/iio/pressure/st_pressure_spi.c
> @@ -86,24 +86,13 @@ static int st_press_spi_probe(struct spi_device *spi)
>  	if (err)
>  		return err;
>  
> -	err = st_press_common_probe(indio_dev);
> -	if (err < 0)
> -		goto st_press_power_off;
> -
> -	return 0;
> -
> -st_press_power_off:
> -	st_sensors_power_disable(indio_dev);
> -
> -	return err;
> +	return st_press_common_probe(indio_dev);
>  }
>  
>  static int st_press_spi_remove(struct spi_device *spi)
>  {
>  	struct iio_dev *indio_dev = spi_get_drvdata(spi);
>  
> -	st_sensors_power_disable(indio_dev);
> -
>  	st_press_common_remove(indio_dev);
>  
>  	return 0;
> diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
> index e74b55244f35..fc90c202d15e 100644
> --- a/include/linux/iio/common/st_sensors.h
> +++ b/include/linux/iio/common/st_sensors.h
> @@ -293,8 +293,6 @@ int st_sensors_set_axis_enable(struct iio_dev *indio_dev, u8 axis_enable);
>  
>  int st_sensors_power_enable(struct iio_dev *indio_dev);
>  
> -void st_sensors_power_disable(struct iio_dev *indio_dev);
> -
>  int st_sensors_debugfs_reg_access(struct iio_dev *indio_dev,
>  				  unsigned reg, unsigned writeval,
>  				  unsigned *readval);