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

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Message-ID: <CAHp75VdeD6zDc--R4NPHsiqQerzfNGwUikLN+WHMiZZVsQ8QSA@mail.gmail.com>
Date:   Fri, 5 Jun 2020 11:14:17 +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 12:14 AM Michael Walle <michael@...le.cc> wrote:
>
> Add support for the watchdog of the sl28cpld board management
> controller. This is part of a multi-function device driver.

...

> +#include <linux/of_device.h>

Didn't find a user of this.

...

> +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...

...

> +       int ret;
> +
> +       ret = regmap_read(wdt->regmap, wdt->offset + WDT_COUNT, &val);
> +
> +       return (ret < 0) ? 0 : val;

Besides extra parentheses and questionable ' < 0' part, the following
would look better I think

ret = ...
if (ret)
  return 0;

return val;

...

> +       int ret;
> +
> +       ret = regmap_write(wdt->regmap, wdt->offset + WDT_TIMEOUT, timeout);
> +       if (!ret)
> +               wdd->timeout = timeout;
> +
> +       return ret;

Similar story here:

ret = ...
if (ret)
  return ret;

wdd->... = ...
return 0;

...

> +       ret = regmap_read(wdt->regmap, wdt->offset + WDT_CTRL, &status);

> +       if (ret < 0)

What ' < 0' means? Do we have some positive return values?
Ditto for all your code.

> +               return ret;

...

> +       if (status & WDT_CTRL_EN) {
> +               sl28cpld_wdt_start(wdd);

> +               set_bit(WDOG_HW_RUNNING, &wdd->status);

Do you need atomic op here? Why?

> +       }

...

> +static const struct of_device_id sl28cpld_wdt_of_match[] = {
> +       { .compatible = "kontron,sl28cpld-wdt" },

> +       {},

No comma.

> +};

-- 
With Best Regards,
Andy Shevchenko