linux-kernel - Re: [PATCH 03/10] watchdog: rzg2l_wdt: Check return status of pm_runtime

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Message-ID: <c857cdd4-459b-41ae-b4bb-0da45e461335@roeck-us.net>
Date: Mon, 22 Jan 2024 09:31:59 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Claudiu <claudiu.beznea@...on.dev>, wim@...ux-watchdog.org,
 robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 geert+renesas@...der.be, magnus.damm@...il.com, mturquette@...libre.com,
 sboyd@...nel.org, p.zabel@...gutronix.de, biju.das.jz@...renesas.com
Cc: linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
 linux-clk@...r.kernel.org, Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH 03/10] watchdog: rzg2l_wdt: Check return status of
 pm_runtime_put()

On 1/22/24 03:11, Claudiu wrote:
> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> 
> pm_runtime_put() may return an error code. Check its return status.
> 
> Fixes: 2cbc5cd0b55f ("watchdog: Add Watchdog Timer driver for RZ/G2L")
> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> ---
>   drivers/watchdog/rzg2l_wdt.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
> index 4ab9e7c5e771..0554965027cd 100644
> --- a/drivers/watchdog/rzg2l_wdt.c
> +++ b/drivers/watchdog/rzg2l_wdt.c
> @@ -144,9 +144,13 @@ static int rzg2l_wdt_start(struct watchdog_device *wdev)
>   static int rzg2l_wdt_stop(struct watchdog_device *wdev)
>   {
>   	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	int ret;
>   
>   	rzg2l_wdt_reset(priv);
> -	pm_runtime_put(wdev->parent);
> +
> +	ret = pm_runtime_put(wdev->parent);
> +	if (ret < 0)
> +		return ret;
>   
>   	return 0;
>   }

A simple
	return pm_runtime_put();
might do.

However, one question: Given that pm_runtime_put() returns -ENOSYS if
CONFIG_PM is disabled, that means the driver will depend on CONFIG_PM=y.
Assuming this is intentional, would it make sense to explicitly declare
that dependency in Kconfig ? It doesn't seem to make any sense to build
the driver if it won't work anyway.

Thanks,
Guenter