linux-kernel - Re: [PATCH v4 8/9] watchdog: max77620: add comment to clarify set

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Date:   Mon, 29 Nov 2021 17:08:45 +0100
From:   Luca Ceresoli <luca@...aceresoli.net>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     linux-kernel@...r.kernel.org, Lee Jones <lee.jones@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        devicetree@...r.kernel.org, linux-rtc@...r.kernel.org,
        linux-watchdog@...r.kernel.org,
        Chiwoong Byun <woong.byun@...sung.com>,
        Laxman Dewangan <ldewangan@...dia.com>,
        Randy Dunlap <rdunlap@...radead.org>
Subject: Re: [PATCH v4 8/9] watchdog: max77620: add comment to clarify
 set_timeout procedure

Hi Guenter,

On 29/11/21 17:04, Guenter Roeck wrote:
> On Sat, Nov 20, 2021 at 04:57:06PM +0100, Luca Ceresoli wrote:
>> Clarify why we need to ping the watchdog before changing the timeout by
>> quoting the MAX77714 datasheet.
>>
> 
> Unless I am missing something, this adds confusion instead of clarifying
> anything, and it is misleading. The added comment in the code makes it
> sound like clearing the watchdog timer is only needed for MAX77614.
> However, the code was in place for MAX77620, suggesting that it was needed
> for that chip as well and is not MAX77614 specific.

You're right, the comment comes from the max77714-only driver, but now
that it is in a multi-chip  driver the confusion started to exist.

> Please either drop this patch or rephrase it to clarify that it applies
> to both chips.

What if I rephrase to:

	/*
	 * "If the value of TWD needs to be changed, clear the system
	 * watchdog timer first [...], then change the value of TWD."
-	 * (MAX77714 datasheet)
+	 * (MAX77714 datasheet but applies to MAX77620 too)
	 */

?

-- 
Luca