Re: [PATCH v2] iio: adc: ti-ads1015: use devm helpers to fix probe error paths

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 29 May 2026 23:37:08 +0500
Stepan Ionichev <sozdayvek@gmail.com> wrote:

> Once ads1015_probe() gets past ads1015_set_conv_mode(CONTINUOUS), two
> resources leak on its error paths and on driver unbind:
> 
>   - pm_runtime_enable() is left enabled if iio_device_register() fails;
>     on subsequent probe/rebind the runtime PM tracking complains about
>     an unbalanced enable.
>   - The CONTINUOUS conversion mode written to the chip is never restored
>     on any error path after that point, so on probe failure the chip is
>     left running.
> 
> Convert all three teardown operations of ads1015_remove() to devm so
> that the error paths and the unbind path share the same unwind in
> reverse-of-setup order:
> 
>   - ads1015_set_conv_mode(SINGLESHOT) becomes a devm action registered
>     immediately after CONTINUOUS mode is enabled.
>   - pm_runtime_enable() becomes devm_pm_runtime_enable().
>   - iio_device_register() becomes devm_iio_device_register(), so the
>     iio device is unregistered first on unbind.
> 
> ads1015_remove() is no longer needed and is dropped.
> 
> Signed-off-by: Stepan Ionichev <sozdayvek@gmail.com>
These are always a bit fiddly so I was hoping to get some more eyes on this
one.  Ah well, long enough and I think it's fine and sashiko is happy so applied.

Thanks,

Jonathan

> ---
> v2:
> - Full devm conversion: register a devm action for set_conv_mode(SINGLESHOT),
>   switch to devm_iio_device_register, drop ads1015_remove() entirely.  This
>   avoids mixing devm with manual unwind (Jonathan) and also fixes the
>   pre-existing continuous-mode leak on probe failure.
> - Drop the unrelated dev_err() -> dev_err_probe() conversion from v1 (Joshua).
> 
> v1: https://lore.kernel.org/all/20260529101011.3030-1-sozdayvek@gmail.com/
> 
>  drivers/iio/adc/ti-ads1015.c | 44 +++++++++++++++---------------------
>  1 file changed, 18 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-ads1015.c b/drivers/iio/adc/ti-ads1015.c
> index c7ffe47449e2..d7f4d0d5bcf9 100644
> --- a/drivers/iio/adc/ti-ads1015.c
> +++ b/drivers/iio/adc/ti-ads1015.c
> @@ -930,6 +930,17 @@ static int ads1015_set_conv_mode(struct ads1015_data *data, int mode)
>  				  mode << ADS1015_CFG_MOD_SHIFT);
>  }
>  
> +static void ads1015_power_down(void *p)
> +{
> +	struct ads1015_data *data = p;
> +	int ret;
> +
> +	ret = ads1015_set_conv_mode(data, ADS1015_SINGLESHOT);
> +	if (ret)
> +		dev_warn(regmap_get_device(data->regmap),
> +			 "Failed to power down (%pe)\n", ERR_PTR(ret));
> +}
> +
>  static int ads1015_probe(struct i2c_client *client)
>  {
>  	const struct ads1015_chip_data *chip;
> @@ -1030,6 +1041,10 @@ static int ads1015_probe(struct i2c_client *client)
>  	if (ret)
>  		return ret;
>  
> +	ret = devm_add_action_or_reset(&client->dev, ads1015_power_down, data);
> +	if (ret)
> +		return ret;
> +
>  	data->conv_invalid = true;
>  
>  	ret = pm_runtime_set_active(&client->dev);
> @@ -1037,33 +1052,11 @@ static int ads1015_probe(struct i2c_client *client)
>  		return ret;
>  	pm_runtime_set_autosuspend_delay(&client->dev, ADS1015_SLEEP_DELAY_MS);
>  	pm_runtime_use_autosuspend(&client->dev);
> -	pm_runtime_enable(&client->dev);
> -
> -	ret = iio_device_register(indio_dev);
> -	if (ret < 0) {
> -		dev_err(&client->dev, "Failed to register IIO device\n");
> +	ret = devm_pm_runtime_enable(&client->dev);
> +	if (ret)
>  		return ret;
> -	}
> -
> -	return 0;
> -}
>  
> -static void ads1015_remove(struct i2c_client *client)
> -{
> -	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> -	struct ads1015_data *data = iio_priv(indio_dev);
> -	int ret;
> -
> -	iio_device_unregister(indio_dev);
> -
> -	pm_runtime_disable(&client->dev);
> -	pm_runtime_set_suspended(&client->dev);
> -
> -	/* power down single shot mode */
> -	ret = ads1015_set_conv_mode(data, ADS1015_SINGLESHOT);
> -	if (ret)
> -		dev_warn(&client->dev, "Failed to power down (%pe)\n",
> -			 ERR_PTR(ret));
> +	return devm_iio_device_register(&client->dev, indio_dev);
>  }
>  
>  #ifdef CONFIG_PM
> @@ -1150,7 +1143,6 @@ static struct i2c_driver ads1015_driver = {
>  		.pm = &ads1015_pm_ops,
>  	},
>  	.probe		= ads1015_probe,
> -	.remove		= ads1015_remove,
>  	.id_table	= ads1015_id,
>  };
>