Re: [PATCH v2 3/3] iio: imu: inv_mpu6050: fix unbalanced regulator_disable calls, when probe fails

[Nuno Sá]

On Wed, 2026-04-01 at 11:27 +0300, Andrey Skvortsov wrote:
> During a probe functions after all regulators are enabled, runtime pm
> is enabled. Before probe function finishes, runtime pm triggers and
> disables vddio regulator. When probe function fails after that,
> inv_mpu_core_disable_regulator_action tries to disable already
> disabled by runtime pm vddio regulator causing following backtrace:
> 
>   inv-mpu6050-i2c 1-0068: trigger probe fail -19
>   WARNING: drivers/regulator/core.c:3244 at _regulator_disable+0x2ac/0x600
>   Call trace:
>    _regulator_disable+0x2ac/0x600 (P)
>    regulator_disable+0xac/0x148
>    inv_mpu_core_disable_regulator_vddio_action+0x3c/0xb0 [inv_mpu6050]
>    devm_action_release+0x4c/0x88
>    release_nodes+0xd8/0x178
>    devres_release_group+0x214/0x3c8
>    i2c_device_probe+0x6fc/0x9b0
>   ...
>   inv-mpu6050-i2c 1-0068: Failed to disable vddio regulator: -5
> 
> Fix the issue by checking runtime suspend status, when vddio regulator
> is disabled. To handle this correctly pm_runtime active status has to
> be set early before vddio regulator setup.

The above looks a bit hacky. We're playing with runtime status for things to work.
Also, setting the active state makes sense logically when the device is up and
running.

Maybe we should just move enabling runtime to the end of the probe function?

Also, fixes should come first in the series in case we want to backport them.

- Nuno Sá
> 
> Signed-off-by: Andrey Skvortsov <andrej.skvortzov@xxxxxxxxx>
> Fixes: 07c12b1c007c ("iio: imu: mpu6050: add support for regulator framework")
> ---
>  drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> index 3a57a3f440526..86e4d42c4d3d1 100644
> --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
> @@ -1862,8 +1862,10 @@ static int inv_mpu_core_disable_regulator_vddio(struct
> inv_mpu6050_state *st)
>  static void inv_mpu_core_disable_regulator_vddio_action(void *_data)
>  {
>  	struct inv_mpu6050_state *st = _data;
> +	struct device *dev = regmap_get_device(st->map);
>  
> -	inv_mpu_core_disable_regulator_vddio(st);
> +	if (!pm_runtime_status_suspended(dev))
> +		inv_mpu_core_disable_regulator_vddio(st);
>  }
>  
>  
> @@ -1953,6 +1955,11 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const
> char *name,
>  
>  	msleep(INV_MPU6050_POWER_UP_TIME);
>  
> +	/* set pm_runtime active early for disable vddio resource cleanup */
> +	result = pm_runtime_set_active(dev);
> +	if (result)
> +		return result;
> +
>  	result = inv_mpu_core_enable_regulator_vddio(st);
>  	if (result)
>  		return result;
> @@ -1996,9 +2003,6 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const
> char *name,
>  	}
>  
>  	/* chip init is done, turning on runtime power management */
> -	result = pm_runtime_set_active(dev);
> -	if (result)
> -		goto error_power_off;
>  	pm_runtime_get_noresume(dev);
>  	result = devm_pm_runtime_enable(dev);
>  	if (result)