From: Guenter Roeck <linux@roeck-us.net>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>,
linux-watchdog@vger.kernel.org,
linux-renesas-soc@vger.kernel.org,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Subject: Re: [PATCH] watchdog: renesas_wdt: adapt timer setup to recommended procedure
Date: Tue, 27 Feb 2018 07:03:29 -0800 [thread overview]
Message-ID: <86da4e12-0d0c-c07a-eecd-76466f713da1@roeck-us.net> (raw)
In-Reply-To: <20180227130058.pmgo33zjvbxwmlad@ninjato>
On 02/27/2018 05:00 AM, Wolfram Sang wrote:
>>> - rwdt_write(priv, 0, RWTCSRB);
>>> - rwdt_write(priv, priv->cks, RWTCSRA);
>>
>> Isn't this done implicitly with the above already ?
>> After all, priv->cks won't have RWTCSRA_TME set.
>
> Yes. The request came from a group doing some (safety?) audit who didn't
> like the implicit handling which might change if the code in probe()
> might change somewhen. And the datasheet explicitly says to disable the
> timer first before doing anything with the clock dividers. Given that, I
> can agree to this change, too.
>
Defensive code is fine, bit that is a bit too defensive. We might as well
start checking value ranges in the drivers' set_timeout functions just in case
the core gets it wrong. Just add a note to the probe function where cks is
initialized that RWTCSRA_TME must not be set, and that RWTCSRA_TME must be
cleared before changing the divider.
Guenter
next prev parent reply other threads:[~2018-02-27 15:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-26 21:49 [PATCH] watchdog: renesas_wdt: adapt timer setup to recommended procedure Wolfram Sang
2018-02-26 22:38 ` Guenter Roeck
2018-02-27 13:00 ` Wolfram Sang
2018-02-27 15:03 ` Guenter Roeck [this message]
2018-02-27 16:22 ` Wolfram Sang
2018-02-27 17:19 ` Guenter Roeck
2018-02-27 20:36 ` Wolfram Sang
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