linux-kernel - Re: [PATCH 1/3] watchdog: s3c2410_wdt: Fold s3c2410_get_wdt_drv

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Date:   Mon, 6 Mar 2023 10:12:21 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        linux-samsung-soc@...r.kernel.org,
        Alim Akhtar <alim.akhtar@...sung.com>,
        linux-kernel@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        kernel@...gutronix.de, Wim Van Sebroeck <wim@...ux-watchdog.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-watchdog@...r.kernel.org
Subject: Re: [PATCH 1/3] watchdog: s3c2410_wdt: Fold
 s3c2410_get_wdt_drv_data() into only caller

On 3/6/23 09:47, Uwe Kleine-König wrote:
> On Mon, Mar 06, 2023 at 09:17:23AM -0800, Guenter Roeck wrote:
>> On 3/6/23 01:09, Uwe Kleine-König wrote:
>>> s3c2410_get_wdt_drv_data() is only called by s3c2410wdt_probe(), so the
>>> implementation of the former can move to the latter.
>>>
>>> scripts/bloat-o-meter reports for this change (on an ARCH=arm
>>> allmodconfig build):
>>>
>>> 	add/remove: 1/1 grow/shrink: 0/2 up/down: 4/-129 (-125)
>>>
>>
>> The reason for separating functions in this case wasn't that the separate function
>> would be called several times. It was to improve code readability. If anything,
>> I would argue that it might sense to split the already lengthy probe function
>> further instead of combining it.
> 
> Agreed. For dev_err_probe() to work the following would be alternatively
> possible:
> 

That looks ok to me.

Thanks,
Guenter

> diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> index 58b262ca4e88..564919717761 100644
> --- a/drivers/watchdog/s3c2410_wdt.c
> +++ b/drivers/watchdog/s3c2410_wdt.c
> @@ -579,8 +579,8 @@ static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
>   	return 0;
>   }
>   
> -static inline const struct s3c2410_wdt_variant *
> -s3c2410_get_wdt_drv_data(struct platform_device *pdev)
> +static inline int
> +s3c2410_get_wdt_drv_data(struct platform_device *pdev, struct s3c2410_wdt *wdt)
>   {
>   	const struct s3c2410_wdt_variant *variant;
>   	struct device *dev = &pdev->dev;
> @@ -603,24 +603,26 @@ s3c2410_get_wdt_drv_data(struct platform_device *pdev)
>   					   "samsung,cluster-index", &index);
>   		if (err) {
>   			dev_err(dev, "failed to get cluster index\n");
> -			return NULL;
> +			return -EINVAL;
>   		}
>   
>   		switch (index) {
>   		case 0:
> -			return variant;
> +			break;
>   		case 1:
> -			return (variant == &drv_data_exynos850_cl0) ?
> +			variant = (variant == &drv_data_exynos850_cl0) ?
>   				&drv_data_exynos850_cl1 :
>   				&drv_data_exynosautov9_cl1;
> +			break;
>   		default:
>   			dev_err(dev, "wrong cluster index: %u\n", index);
> -			return NULL;
> +			return -EINVAL;
>   		}
>   	}
>   #endif
> +	wdt->drv_data = variant;
>   
> -	return variant;
> +	return 0;
>   }
>   
>   static void s3c2410wdt_wdt_disable_action(void *data)
> @@ -644,9 +646,9 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
>   	spin_lock_init(&wdt->lock);
>   	wdt->wdt_device = s3c2410_wdd;
>   
> -	wdt->drv_data = s3c2410_get_wdt_drv_data(pdev);
> -	if (!wdt->drv_data)
> -		return -EINVAL;
> +	ret = s3c2410_get_wdt_drv_data(pdev, wdt);
> +	if (ret)
> +		return ret;
>   
>   	if (wdt->drv_data->quirks & QUIRKS_HAVE_PMUREG) {
>   		wdt->pmureg = syscon_regmap_lookup_by_phandle(dev->of_node,
> 
> I didn't check if it's the same as for my initial patch #1, but for an
> allmodconfig ARCH=arm build this also has a nice bloatometer output:
> 
> 	add/remove: 1/1 grow/shrink: 0/1 up/down: 4/-104 (-100)
> 
> This would allow to make use of dev_err_probe() in
> s3c2410_get_wdt_drv_data() and still maintain the split into two
> functions.
> 
> Best regards
> Uwe
>