Re: [PATCH v2] iio: pressure: mpl115: Fix runtime PM cleanup

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 20 Jul 2026 10:43:12 +0800
Can Peng <pengcan@kylinos.cn> wrote:

> mpl115_probe() enables runtime PM when a shutdown GPIO is present and
> then returns the result of devm_iio_device_register(). If registration
> fails, runtime PM remains enabled and autosuspend remains selected.
> 
> The same unmanaged runtime PM state is also left behind on driver
> unbind, as the IIO device registration is managed but the runtime PM
> setup is not.
> 
> Use devm_pm_runtime_enable() so runtime PM is disabled automatically on
> probe failure and driver unbind, and check pm_runtime_set_active() so
> setup errors are reported.
> 
> Set the autosuspend parameters before enabling runtime PM. Once probe
> has completed, the driver core queues an idle request for the device, so
> an explicit pm_runtime_get_noresume()/pm_runtime_put() pair is not
> needed to start autosuspend.
> 
> Fixes: 0c3a333524a3 ("iio: pressure: mpl115: Implementing low power mode by shutdown gpio")
> Cc: stable@vger.kernel.org
> Suggested-by: jonathan.cameron@oss.qualcomm.com
> Signed-off-by: Can Peng <pengcan@kylinos.cn>
Hi,

Looks good to me. I'm going to take it the slow path via the next
merge window as it is a fairly low impact bug.

Applied to the testing branch of iio.git

Thanks,

Jonathan

> ---
> Changes in v2:
> - Drop the explicit pm_runtime_get_noresume()/pm_runtime_put() pair and
>   rely on the driver core idle request after probe.
> - Set autosuspend parameters before enabling runtime PM.
> - Update the commit message accordingly.
> - Link to v1: https://lore.kernel.org/all/20260718061909.428476-1-pengcan@kylinos.cn/
> 
>  drivers/iio/pressure/mpl115.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/pressure/mpl115.c b/drivers/iio/pressure/mpl115.c
> index 16e112b796ba..2929ea8e4e01 100644
> --- a/drivers/iio/pressure/mpl115.c
> +++ b/drivers/iio/pressure/mpl115.c
> @@ -203,9 +203,9 @@ int mpl115_probe(struct device *dev, const char *name,
>  
>  	if (data->shutdown) {
>  		/* Enable runtime PM */
> -		pm_runtime_get_noresume(dev);
> -		pm_runtime_set_active(dev);
> -		pm_runtime_enable(dev);
> +		ret = pm_runtime_set_active(dev);
> +		if (ret)
> +			return ret;
>  
>  		/*
>  		 * As the device takes 3 ms to come up with a fresh
> @@ -215,7 +215,10 @@ int mpl115_probe(struct device *dev, const char *name,
>  		 */
>  		pm_runtime_set_autosuspend_delay(dev, 2000);
>  		pm_runtime_use_autosuspend(dev);
> -		pm_runtime_put(dev);
> +
> +		ret = devm_pm_runtime_enable(dev);
> +		if (ret)
> +			return ret;
>  
>  		dev_dbg(dev, "low-power mode enabled");
>  	} else