Re: [PATCH v4 06/10] gpio: mxc: convert probe error handling to devres

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] pm: usage counter underflow due to mixed devm and manual autosuspend
--

commit dc287cc46ea891b838f3b39a1fd6ed65d627a965
Author: Peng Fan <peng.fan@nxp.com>

    gpio: mxc: convert probe error handling to devres
    
    This patch converts the driver's probe error handling to use devres. It
    replaces irq_domain_create_legacy() with devm_irq_domain_instantiate()
    and updates the PM runtime initialization to use devm_ variants, eliminating
    the need for manual cleanup labels.

> diff --git a/drivers/gpio/gpio-mxc.c b/drivers/gpio/gpio-mxc.c
> index 5da603569d88d..54b09f1a4b509 100644
> --- a/drivers/gpio/gpio-mxc.c
> +++ b/drivers/gpio/gpio-mxc.c
> @@ -484,9 +485,13 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	if (IS_ERR(port->clk))
>  		return PTR_ERR(port->clk);
>  
> -	pm_runtime_get_noresume(&pdev->dev);
> -	pm_runtime_set_active(&pdev->dev);
> -	pm_runtime_enable(&pdev->dev);
> +	err = devm_pm_runtime_get_noresume(&pdev->dev);
> +	if (err)
> +		return dev_err_probe(&pdev->dev, err, "Failed to get PM runtime\n");
> +
> +	err = devm_pm_runtime_set_active_enabled(&pdev->dev);
> +	if (err)
> +		return dev_err_probe(&pdev->dev, err, "Failed to enable PM runtime\n");

[ ... ]

> @@ -558,14 +567,6 @@ static int mxc_gpio_probe(struct platform_device *pdev)
>  	pm_runtime_put_autosuspend(&pdev->dev);

[Severity: High]
Since devm_pm_runtime_get_noresume() increments the usage counter and queues
a devres action to drop it on unbind, will this manual call to
pm_runtime_put_autosuspend() cause an issue?

Because the devres action remains queued, when the device is unbound (e.g.,
via device tree overlay removal or hot-unplug), the devres cleanup will
execute and decrement the usage counter a second time. Could this cause a PM
usage counter underflow, corrupting the device and parent power state?

>  
>  	return 0;
> -
> -out_irqdomain_remove:
> -	irq_domain_remove(port->domain);
> -out_bgio:
> -	pm_runtime_disable(&pdev->dev);
> -	pm_runtime_put_noidle(&pdev->dev);
> -	dev_info(&pdev->dev, "%s failed with errno %d\n", __func__, err);
> -	return err;
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261007-gpio-mxc-cleanup-v4-0-c9f5a8b50df9@nxp.com?part=6