On Sat, 31 Jul 2021 at 20:34, Jonathan Cameron [off-list ref] wrote:

On Mon, 26 Jul 2021 10:14:02 +0300
Alexandru Ardelean [off-list ref] wrote:

quoted

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 ;)

Probably the best advantage of devm_ functions .
Not needing to care about un-init order.

I hated debugging driver crashes when they were unloaded, usually
because the driver gets into a weird state.

I'll send a V2 with the re-order fixes in the front.

quoted

Signed-off-by: Alexandru Ardelean <redacted>
---
 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);