linux-kernel - Re: [PATCH v4 04/11] watchdog: add support for sl28cpld watchdog

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Date:   Fri, 5 Jun 2020 13:50:43 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Michael Walle <michael@...le.cc>
Cc:     "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-hwmon@...r.kernel.org, linux-pwm@...r.kernel.org,
        linux-watchdog@...r.kernel.org,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Lee Jones <lee.jones@...aro.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Shawn Guo <shawnguo@...nel.org>, Li Yang <leoyang.li@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <maz@...nel.org>, Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH v4 04/11] watchdog: add support for sl28cpld watchdog

On Fri, Jun 5, 2020 at 1:24 PM Michael Walle <michael@...le.cc> wrote:
> Am 2020-06-05 10:14, schrieb Andy Shevchenko:
> > On Fri, Jun 5, 2020 at 12:14 AM Michael Walle <michael@...le.cc> wrote:

...

> >> +static bool nowayout = WATCHDOG_NOWAYOUT;
> >> +module_param(nowayout, bool, 0);
> >> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started
> >> (default="
> >> +                               __MODULE_STRING(WATCHDOG_NOWAYOUT)
> >> ")");
> >> +
> >> +static int timeout;
> >> +module_param(timeout, int, 0);
> >> +MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds");
> >
> > Guenter ACKed this, but I'm wondering why we still need module
> > parameters...
>
> How would a user change the nowayout or the timeout? For the latter
> there is
> a device tree entry, but thats not easy changable by the user.

Yes, it's more question to VIm and Guenter than to you.

...

> >> +       if (status & WDT_CTRL_EN) {
> >> +               sl28cpld_wdt_start(wdd);
> >
> >> +               set_bit(WDOG_HW_RUNNING, &wdd->status);
> >
> > Do you need atomic op here? Why?
>
> I'd say consistency, all watchdog drivers do it like that. I just
> had a look at where this is used, but it looks like access from
> userspace is protected by a lock.

Okay then.

-- 
With Best Regards,
Andy Shevchenko