linux-kernel - Re: [PATCH 2/7] watchdog: jz4740: Use devm

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Message-ID: <9778afd4-5841-0d48-cde3-c02872623a5f@roeck-us.net>
Date:   Thu, 28 Dec 2017 09:48:09 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Paul Cercueil <paul@...pouillou.net>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Wim Van Sebroeck <wim@...ana.be>
Cc:     devicetree@...r.kernel.org, linux-mips@...ux-mips.org,
        linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org
Subject: Re: [PATCH 2/7] watchdog: jz4740: Use devm_* functions

On 12/28/2017 08:29 AM, Paul Cercueil wrote:
> - Use devm_clk_get instead of clk_get
> - Use devm_watchdog_register_device instead of watchdog_register_device
> 
> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> ---
>   drivers/watchdog/jz4740_wdt.c | 27 ++++++++-------------------
>   1 file changed, 8 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c
> index 6955deb100ef..92d6ca8ceb49 100644
> --- a/drivers/watchdog/jz4740_wdt.c
> +++ b/drivers/watchdog/jz4740_wdt.c
> @@ -178,40 +178,29 @@ static int jz4740_wdt_probe(struct platform_device *pdev)
>   
>   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   	drvdata->base = devm_ioremap_resource(&pdev->dev, res);
> -	if (IS_ERR(drvdata->base)) {
> -		ret = PTR_ERR(drvdata->base);
> -		goto err_out;
> -	}
> +	if (IS_ERR(drvdata->base))
> +		return PTR_ERR(drvdata->base);
>   
> -	drvdata->rtc_clk = clk_get(&pdev->dev, "rtc");
> +	drvdata->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
>   	if (IS_ERR(drvdata->rtc_clk)) {
>   		dev_err(&pdev->dev, "cannot find RTC clock\n");
> -		ret = PTR_ERR(drvdata->rtc_clk);
> -		goto err_out;
> +		return PTR_ERR(drvdata->rtc_clk);
>   	}
>   
> -	ret = watchdog_register_device(&drvdata->wdt);
> +	ret = devm_watchdog_register_device(&pdev->dev, &drvdata->wdt);
>   	if (ret < 0)
> -		goto err_disable_clk;
> +		return ret;
>   
>   	platform_set_drvdata(pdev, drvdata);
> -	return 0;
>   
> -err_disable_clk:
> -	clk_put(drvdata->rtc_clk);
> -err_out:
> -	return ret;
> +	return 0;
>   }
>   
>   static int jz4740_wdt_remove(struct platform_device *pdev)
>   {
>   	struct jz4740_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
>   
> -	jz4740_wdt_stop(&drvdata->wdt);
> -	watchdog_unregister_device(&drvdata->wdt);
> -	clk_put(drvdata->rtc_clk);
> -
> -	return 0;
> +	return jz4740_wdt_stop(&drvdata->wdt);

If the watchdog is running, the module can not be unloaded. Even if that wasn't
the case, this defeats both WDIOF_MAGICCLOSE and watchdog_set_nowayout().
Are you sure this is what you want ? If so, please call
watchdog_stop_on_unregister() before registration; this clarifies that this
is what you want, and you can drop the remove function.

Thanks,
Guenter

>   }
>   
>   static struct platform_driver jz4740_wdt_driver = {
>