linux-kernel - Re: [PATCH] watchdog: imx2

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Message-ID: <968aab4e-50ed-83d2-cac1-d0a216060628@roeck-us.net>
Date:   Sun, 23 Feb 2020 20:04:32 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Anson Huang <Anson.Huang@....com>, wim@...ux-watchdog.org,
        shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
        festevam@...il.com, linux-watchdog@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Linux-imx@....com
Subject: Re: [PATCH] watchdog: imx2_wdt: Drop .remove callback

On 2/23/20 6:51 PM, Anson Huang wrote:
> .remove callback implementation doesn' call clk_disable_unprepare() which
> is buggy, actually, we can just use devm_watchdog_register_device() and
> devm_add_action_or_reset() to handle all necessary operations for remove
> action, then .remove callback can be dropped.
> 
> Signed-off-by: Anson Huang <Anson.Huang@....com>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>   drivers/watchdog/imx2_wdt.c | 37 ++++++++++---------------------------
>   1 file changed, 10 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
> index f8d58bf..1fe472f 100644
> --- a/drivers/watchdog/imx2_wdt.c
> +++ b/drivers/watchdog/imx2_wdt.c
> @@ -244,6 +244,11 @@ static const struct regmap_config imx2_wdt_regmap_config = {
>   	.max_register = 0x8,
>   };
>   
> +static void imx2_wdt_action(void *data)
> +{
> +	clk_disable_unprepare(data);
> +}
> +
>   static int __init imx2_wdt_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
> @@ -292,6 +297,10 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
>   	if (ret)
>   		return ret;
>   
> +	ret = devm_add_action_or_reset(dev, imx2_wdt_action, wdev->clk);
> +	if (ret)
> +		return ret;
> +
>   	regmap_read(wdev->regmap, IMX2_WDT_WRSR, &val);
>   	wdog->bootstatus = val & IMX2_WDT_WRSR_TOUT ? WDIOF_CARDRESET : 0;
>   
> @@ -315,32 +324,7 @@ static int __init imx2_wdt_probe(struct platform_device *pdev)
>   	 */
>   	regmap_write(wdev->regmap, IMX2_WDT_WMCR, 0);
>   
> -	ret = watchdog_register_device(wdog);
> -	if (ret)
> -		goto disable_clk;
> -
> -	dev_info(dev, "timeout %d sec (nowayout=%d)\n",
> -		 wdog->timeout, nowayout);
> -
> -	return 0;
> -
> -disable_clk:
> -	clk_disable_unprepare(wdev->clk);
> -	return ret;
> -}
> -
> -static int __exit imx2_wdt_remove(struct platform_device *pdev)
> -{
> -	struct watchdog_device *wdog = platform_get_drvdata(pdev);
> -	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
> -
> -	watchdog_unregister_device(wdog);
> -
> -	if (imx2_wdt_is_running(wdev)) {
> -		imx2_wdt_ping(wdog);
> -		dev_crit(&pdev->dev, "Device removed: Expect reboot!\n");
> -	}
> -	return 0;
> +	return devm_watchdog_register_device(dev, wdog);
>   }
>   
>   static void imx2_wdt_shutdown(struct platform_device *pdev)
> @@ -417,7 +401,6 @@ static const struct of_device_id imx2_wdt_dt_ids[] = {
>   MODULE_DEVICE_TABLE(of, imx2_wdt_dt_ids);
>   
>   static struct platform_driver imx2_wdt_driver = {
> -	.remove		= __exit_p(imx2_wdt_remove),
>   	.shutdown	= imx2_wdt_shutdown,
>   	.driver		= {
>   		.name	= DRIVER_NAME,
>