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Subject: Re: [PATCH 10/23] watchdog: of_xilinx_wdt: Convert to use device
 managed functions and other improvements
To:     Guenter Roeck <linux@roeck-us.net>,
        Wim Van Sebroeck <wim@linux-watchdog.org>
CC:     <linux-watchdog@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Michal Simek <michal.simek@xilinx.com>
References: <1554830641-9247-1-git-send-email-linux@roeck-us.net>
 <1554830641-9247-11-git-send-email-linux@roeck-us.net>
From:   Michal Simek <michal.simek@xilinx.com>
Message-ID: <85e92d6f-5521-af0a-f6e0-b3411b7cd8e9@xilinx.com>
Date:   Wed, 10 Apr 2019 08:38:14 +0200
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On 09. 04. 19 19:23, Guenter Roeck wrote:
> Use device managed functions to simplify error handling, reduce
> source code size, improve readability, and reduce the likelyhood of bugs.
> Other improvements as listed below.
> 
> The conversion was done automatically with coccinelle using the
> following semantic patches. The semantic patches and the scripts
> used to generate this commit log are available at
> https://github.com/groeck/coccinelle-patches
> 
> - Drop assignments to otherwise unused variables
> - Drop empty remove function
> - Use devm_add_action_or_reset() for calls to clk_disable_unprepare
> - Introduce local variable 'struct device *dev' and use it instead of
>   dereferencing it repeatedly
> - Use devm_watchdog_register_driver() to register watchdog device
> 
> Cc: Michal Simek <michal.simek@xilinx.com>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
>  drivers/watchdog/of_xilinx_wdt.c | 58 ++++++++++++++++++----------------------
>  1 file changed, 26 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
> index 5c977164b3e5..03786992b701 100644
> --- a/drivers/watchdog/of_xilinx_wdt.c
> +++ b/drivers/watchdog/of_xilinx_wdt.c
> @@ -151,41 +151,46 @@ static u32 xwdt_selftest(struct xwdt_device *xdev)
>  		return XWT_TIMER_FAILED;
>  }
>  
> +static void xwdt_clk_disable_unprepare(void *data)
> +{
> +	clk_disable_unprepare(data);
> +}
> +
>  static int xwdt_probe(struct platform_device *pdev)
>  {
> +	struct device *dev = &pdev->dev;
>  	int rc;
>  	u32 pfreq = 0, enable_once = 0;
>  	struct xwdt_device *xdev;
>  	struct watchdog_device *xilinx_wdt_wdd;
>  
> -	xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
> +	xdev = devm_kzalloc(dev, sizeof(*xdev), GFP_KERNEL);
>  	if (!xdev)
>  		return -ENOMEM;
>  
>  	xilinx_wdt_wdd = &xdev->xilinx_wdt_wdd;
>  	xilinx_wdt_wdd->info = &xilinx_wdt_ident;
>  	xilinx_wdt_wdd->ops = &xilinx_wdt_ops;
> -	xilinx_wdt_wdd->parent = &pdev->dev;
> +	xilinx_wdt_wdd->parent = dev;
>  
>  	xdev->base = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(xdev->base))
>  		return PTR_ERR(xdev->base);
>  
> -	rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-interval",
> +	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-interval",
>  				  &xdev->wdt_interval);
>  	if (rc)
> -		dev_warn(&pdev->dev,
> -			 "Parameter \"xlnx,wdt-interval\" not found\n");
> +		dev_warn(dev, "Parameter \"xlnx,wdt-interval\" not found\n");
>  
> -	rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-enable-once",
> +	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-enable-once",
>  				  &enable_once);
>  	if (rc)
> -		dev_warn(&pdev->dev,
> +		dev_warn(dev,
>  			 "Parameter \"xlnx,wdt-enable-once\" not found\n");
>  
>  	watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);
>  
> -	xdev->clk = devm_clk_get(&pdev->dev, NULL);
> +	xdev->clk = devm_clk_get(dev, NULL);
>  	if (IS_ERR(xdev->clk)) {
>  		if (PTR_ERR(xdev->clk) != -ENOENT)
>  			return PTR_ERR(xdev->clk);
> @@ -196,10 +201,10 @@ static int xwdt_probe(struct platform_device *pdev)
>  		 */
>  		xdev->clk = NULL;
>  
> -		rc = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
> +		rc = of_property_read_u32(dev->of_node, "clock-frequency",
>  					  &pfreq);
>  		if (rc)
> -			dev_warn(&pdev->dev,
> +			dev_warn(dev,
>  				 "The watchdog clock freq cannot be obtained\n");
>  	} else {
>  		pfreq = clk_get_rate(xdev->clk);
> @@ -218,44 +223,34 @@ static int xwdt_probe(struct platform_device *pdev)
>  
>  	rc = clk_prepare_enable(xdev->clk);
>  	if (rc) {
> -		dev_err(&pdev->dev, "unable to enable clock\n");
> +		dev_err(dev, "unable to enable clock\n");
>  		return rc;
>  	}
> +	rc = devm_add_action_or_reset(dev, xwdt_clk_disable_unprepare,
> +				      xdev->clk);
> +	if (rc)
> +		return rc;
>  
>  	rc = xwdt_selftest(xdev);
>  	if (rc == XWT_TIMER_FAILED) {
> -		dev_err(&pdev->dev, "SelfTest routine error\n");
> -		goto err_clk_disable;
> +		dev_err(dev, "SelfTest routine error\n");
> +		return rc;
>  	}
>  
> -	rc = watchdog_register_device(xilinx_wdt_wdd);
> +	rc = devm_watchdog_register_device(dev, xilinx_wdt_wdd);
>  	if (rc) {
> -		dev_err(&pdev->dev, "Cannot register watchdog (err=%d)\n", rc);
> -		goto err_clk_disable;
> +		dev_err(dev, "Cannot register watchdog (err=%d)\n", rc);
> +		return rc;
>  	}
>  
>  	clk_disable(xdev->clk);
>  
> -	dev_info(&pdev->dev, "Xilinx Watchdog Timer at %p with timeout %ds\n",
> +	dev_info(dev, "Xilinx Watchdog Timer at %p with timeout %ds\n",
>  		 xdev->base, xilinx_wdt_wdd->timeout);
>  
>  	platform_set_drvdata(pdev, xdev);
>  
>  	return 0;
> -err_clk_disable:
> -	clk_disable_unprepare(xdev->clk);
> -
> -	return rc;
> -}
> -
> -static int xwdt_remove(struct platform_device *pdev)
> -{
> -	struct xwdt_device *xdev = platform_get_drvdata(pdev);
> -
> -	watchdog_unregister_device(&xdev->xilinx_wdt_wdd);
> -	clk_disable_unprepare(xdev->clk);
> -
> -	return 0;
>  }
>  
>  /**
> @@ -303,7 +298,6 @@ MODULE_DEVICE_TABLE(of, xwdt_of_match);
>  
>  static struct platform_driver xwdt_driver = {
>  	.probe       = xwdt_probe,
> -	.remove      = xwdt_remove,
>  	.driver = {
>  		.name  = WATCHDOG_NAME,
>  		.of_match_table = xwdt_of_match,
> 

Looks good to me. I would prefer to do it via 3 patches but I will let
Wim to comment.

Acked-by: Michal Simek <michal.simek@xilinx.com>

Thanks,
Michal