linux-kernel - Re: [PATCH v1 10/11] watchdog: bd9576_wdt: switch to using devm_fwnode_gpiod

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Message-ID: <CAHp75VcisCTYoRp-=713YKtwi7BQyPKGiUhF4DkpfAFtvDXCiQ@mail.gmail.com>
Date:   Mon, 5 Sep 2022 18:21:42 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Matti Vaittinen <mazziesaccount@...il.com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Felipe Balbi <balbi@...nel.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Daniel Vetter <daniel@...ll.ch>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
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        Rob Herring <robh@...nel.org>,
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        USB <linux-usb@...r.kernel.org>,
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Subject: Re: [PATCH v1 10/11] watchdog: bd9576_wdt: switch to using devm_fwnode_gpiod_get()

On Mon, Sep 5, 2022 at 6:13 PM Guenter Roeck <linux@...ck-us.net> wrote:
> On 9/5/22 04:09, Andy Shevchenko wrote:
> > On Mon, Sep 5, 2022 at 9:33 AM Dmitry Torokhov
> > <dmitry.torokhov@...il.com> wrote:

...

> >> +       count = device_property_count_u32(dev->parent, "rohm,hw-timeout-ms");
> >> +       if (count < 0 && count != -EINVAL)
> >> +               return count;
> >> +
> >> +       if (count > 0) {
> >
> >> +               if (count > ARRAY_SIZE(hw_margin))
> >> +                       return -EINVAL;
> >
> > Why double check? You may move it out of the (count > 0).
>
> Two checks will always be needed, so I don't entirely see
> how that would be better.

But not nested. That's my point:

if (count > ARRAY_SIZE())
  return ...
if (count > 0)
  ...

> >> -       if (ret == 1)
> >> -               hw_margin_max = hw_margin[0];
> >
> >> +               ret = device_property_read_u32_array(dev->parent,
> >> +                                                    "rohm,hw-timeout-ms",
> >> +                                                    hw_margin, count);
> >> +               if (ret < 0)
> >> +                       return ret;
> >
> > So, only this needs the count > 0 check since below already has it implicitly.
> >
> Sorry, I don't understand this comment.

if (count > 0) {
  ret = device_property_read_u32_array(...);
  ...
}
if (count == 1)
 ...
if (count == 2)
 ...

But here it might be better to have the nested conditionals.

> >> -       if (ret == 2) {
> >> -               hw_margin_max = hw_margin[1];
> >> -               hw_margin_min = hw_margin[0];
> >> +               if (count == 1)
> >> +                       hw_margin_max = hw_margin[0];
> >> +
> >> +               if (count == 2) {
> >> +                       hw_margin_max = hw_margin[1];
> >> +                       hw_margin_min = hw_margin[0];
> >> +               }
> >>          }

-- 
With Best Regards,
Andy Shevchenko