Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
Date:   Tue, 3 May 2022 11:57:53 +0800
From:   Tzung-Bi Shih <tzungbi@kernel.org>
To:     Pali =?iso-8859-1?Q?Roh=E1r?= <pali@kernel.org>
Cc:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Rob Herring <robh+dt@kernel.org>,
        linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] watchdog: max63xx_wdt: Add support for specifying
 WDI logic via GPIO
Message-ID: <YnCoQUGQsXIfbowQ@google.com>
References: <20220429131349.21229-1-pali@kernel.org>
 <20220429131349.21229-2-pali@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20220429131349.21229-2-pali@kernel.org>
Precedence: bulk

On Fri, Apr 29, 2022 at 03:13:49PM +0200, Pali Roh?r wrote:
> @@ -27,6 +27,7 @@
>  #include <linux/io.h>
>  #include <linux/slab.h>
>  #include <linux/property.h>
> +#include <linux/gpio/consumer.h>

It would be better to keep them alphabetically.  Anyway, they aren't sorted
originally...

> +static void max63xx_gpio_ping(struct max63xx_wdt *wdt)
> +{
> +	spin_lock(&wdt->lock);

Does it really need to acquire the lock?  It looks like the lock is to prevent
concurrent accesses to the mmap in max63xx_mmap_ping() and max63xx_mmap_set().

> +	gpiod_set_value_cansleep(wdt->gpio_wdi, 1);
> +	udelay(1);

Doesn't it need to include <linux/delay.h> for udelay()?

> @@ -225,10 +240,19 @@ static int max63xx_wdt_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> +	wdt->gpio_wdi = devm_gpiod_get(dev, NULL, GPIOD_FLAGS_BIT_DIR_OUT);
> +	if (IS_ERR(wdt->gpio_wdi) && PTR_ERR(wdt->gpio_wdi) != -ENOENT)

Use devm_gpiod_get_optional() to make the intent clear.  Also, it gets rid of
the check for -ENOENT.

> +		return dev_err_probe(dev, PTR_ERR(wdt->gpio_wdi),
> +				     "unable to request gpio: %ld\n",
> +				     PTR_ERR(wdt->gpio_wdi));

It doesn't need to again print for PTR_ERR(wdt->gpio_wdi).  dev_err_probe()
prints the error.

>  	err = max63xx_mmap_init(pdev, wdt);
>  	if (err)
>  		return err;
>  
> +	if (!IS_ERR(wdt->gpio_wdi))
> +		wdt->ping = max63xx_gpio_ping;

Thus, the max63xx_gpio_ping() overrides max63xx_mmap_ping() if the GPIO was
provided?  It would be better to mention the behavior in the commit message.

Also, could both the assignments of `wdt->gpio_wdi` and `wdt->ping` happen
after max63xx_mmap_init()?