Re: [PATCH v2 4/9] watchdog: msc313e: Enable clock before accessing hardware registers

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Probe error path disables the watchdog clock without executing the hardware shutdown sequence, neutralizing the fail-safe.
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commit 0b66291f7c8412075decd0cc0b1b00209ced44cb
Author: Tzung-Bi Shih <tzungbi@kernel.org>
watchdog: msc313e: Enable clock before accessing hardware registers

This commit fixes an issue where msc313e_wdt_probe() accesses hardware
registers before the required clock is enabled. It adds calls to properly
prepare and enable the clock, and ensures the clock reference count remains
balanced if the watchdog is already running at boot.

> diff --git a/drivers/watchdog/msc313e_wdt.c b/drivers/watchdog/msc313e_wdt.c
> index 5dc5e3ab7001e..86e72aea96855 100644
> --- a/drivers/watchdog/msc313e_wdt.c
> +++ b/drivers/watchdog/msc313e_wdt.c
[ ... ]
> @@ -145,7 +158,13 @@ static int msc313e_wdt_probe(struct platform_device *pdev)
>  	watchdog_stop_on_reboot(&priv->wdev);
>  	watchdog_stop_on_unregister(&priv->wdev);
>  
> -	return devm_watchdog_register_device(dev, &priv->wdev);
> +	ret = devm_watchdog_register_device(dev, &priv->wdev);
> +
> +	/* If the WDT is running and anything goes wrong, disable the clock. */
> +	if (ret && test_bit(WDOG_HW_RUNNING, &priv->wdev.status))
> +		clk_disable_unprepare(priv->clk);

[Severity: High]
If devm_watchdog_register_device() fails here, does disabling the clock
without properly executing the hardware shutdown sequence freeze the active
watchdog counter?

If the bootloader armed the watchdog and the probe sequence subsequently fails
(for example, due to a memory allocation failure), it seems gating the clock
without commanding the IP block to stop would neutralize the fail-safe. Does
this leave the system hanging indefinitely instead of allowing the timer to
expire and trigger a protective reset?

> +
> +	return ret;
>  }
>  
>  static int __maybe_unused msc313e_wdt_suspend(struct device *dev)

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Sashiko AI review · https://sashiko.dev/#/patchset/20260828161348.13212-1-tzungbi@kernel.org?part=4