Re: [PATCH v5 09/13] gpio: mxc: use cleanup guard for pm_runtime_get_noresume() balance

[Frank Li <Frank.li@oss.nxp.com>]

On Sat, Oct 10, 2026 at 02:05:30AM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
>
> pm_runtime_get_noresume() in probe must be balanced by
> pm_runtime_put_noidle() on error paths, or pm_runtime_put_autosuspend()
> on success. devm_pm_runtime_get_noresume() cannot be used here because
> its devres action (pm_runtime_put_noidle()) would fire on unbind in
> addition to the success-path pm_runtime_put_autosuspend(), causing a
> usage counter underflow.
>
> Use a __free guard to automatically call pm_runtime_put_noidle() on
> error paths, and disarm it with no_free_ptr() before the success-path
> pm_runtime_put_autosuspend().
>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
>  drivers/gpio/gpio-mxc.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
> index 5ae9cdee6424..3d5a6566d3f4 100644
> --- a/drivers/gpio/gpio-mxc.c
> +++ b/drivers/gpio/gpio-mxc.c
> @@ -445,6 +445,8 @@ static void mxc_update_irq_chained_handler(struct mxc_gpio_port *port, bool enab
>  	}
>  }
>
> +DEFINE_FREE(pm_runtime_put_noidle, struct device *, if (_T) pm_runtime_put_noidle(_T))
> +

This change need put into common runtime_pm.h and like pm maintainer to
review it. Other system may use it, like DMA engine, CSI, ...

And if someone add to common file later, it will cause build error.

>  static int mxc_gpio_probe(struct platform_device *pdev)
>  {
>  	struct gpio_generic_chip_config config = { };
> @@ -486,6 +488,9 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  		return PTR_ERR(port->clk);
>
>  	pm_runtime_get_noresume(dev);
> +
> +	struct device *pm_guard __free(pm_runtime_put_noidle) = dev;
> +
>  	pm_runtime_set_active(dev);
>  	pm_runtime_enable(dev);
>
> @@ -556,6 +561,8 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	mxc_update_irq_chained_handler(port, true);
>
>  	platform_set_drvdata(pdev, port);
> +
> +	pm_guard = no_free_ptr(pm_guard);

use retain_and_null_ptr();

Frank

>  	pm_runtime_put_autosuspend(dev);
>
>  	return 0;
> @@ -564,7 +571,6 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	irq_domain_remove(port->domain);
>  out_bgio:
>  	pm_runtime_disable(dev);
> -	pm_runtime_put_noidle(dev);
>  	dev_info(dev, "%s failed with errno %d\n", __func__, err);
>  	return err;
>  }
>
> --
> 2.51.0
>
>