Re: [PATCH v5 3/8] watchdog: rzv2h: Propagate WDTDCR access errors

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The error path in rzv2h_wdt_stop() leaves the watchdog unconfigured and missing a required delay after reset deassertion.
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commit 3f7bad2568920b818b4bdb62349364febc443827
Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

watchdog: rzv2h: Propagate WDTDCR access errors

The WDTDCR helpers currently access the register directly, but this will
change to use regmap, which can fail. This commit propagates errors from
rzt2h_wdt_wdtdcr_count_start() and rzt2h_wdt_wdtdcr_count_stop() and unwinds
the resources if an error occurs.

> diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
> index 7c6a4855bd8ad..cbf414e0c9a3c 100644
> --- a/drivers/watchdog/rzv2h_wdt.c
> +++ b/drivers/watchdog/rzv2h_wdt.c
[ ... ]
> @@ -169,8 +179,13 @@ static int rzv2h_wdt_stop(struct watchdog_device *wdev)
>  	if (ret)
>  		return ret;
>  
> -	if (priv->of_data->wdtdcr)
> -		rzt2h_wdt_wdtdcr_count_stop(priv);
> +	if (priv->of_data->wdtdcr) {
> +		ret = rzt2h_wdt_wdtdcr_count_stop(priv);
> +		if (ret) {
> +			reset_control_deassert(priv->rstc);
> +			return ret;
> +		}
> +	}
>  
>  	pm_runtime_put(wdev->parent);

[Severity: High]
Does this error path leave the hardware in an uninitialized state?

When rzt2h_wdt_wdtdcr_count_stop() fails in rzv2h_wdt_stop(), the code calls
reset_control_deassert() to bring the hardware out of reset. However, it
does not include the mandatory udelay(3) wait for clock stabilization or
restore the watchdog register configuration via rzv2h_wdt_setup().

This leaves the hardware out of reset but unconfigured, which might trigger an
immediate spurious reboot if default timeouts are active, or fail to reboot
the system during a hang if the watchdog remains dormant.

Could this error handling be updated to fully restore the previous watchdog
state?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260911111731.3404308-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=3