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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 24 May 2021 15:47:47 +0300
Message-ID: <CAHp75VfbdmHPsscHOAnH-WjGyWF-8V_00FjQu1PD+xFLcUytig@mail.gmail.com>
Subject: Re: [PATCH v3 6/6] leds: Add support for RTL8231 LED scan matrix
To:     Sander Vanheule <sander@svanheule.net>
Cc:     Pavel Machek <pavel@ucw.cz>, Rob Herring <robh+dt@kernel.org>,
        Lee Jones <lee.jones@linaro.org>,
        Mark Brown <broonie@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Michael Walle <michael@walle.cc>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Linux LED Subsystem <linux-leds@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Andrew Lunn <andrew@lunn.ch>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, May 24, 2021 at 3:04 PM Sander Vanheule <sander@svanheule.net> wrote:
> On Mon, 2021-05-24 at 13:24 +0300, Andy Shevchenko wrote:
> > On Mon, May 24, 2021 at 1:34 AM Sander Vanheule <sander@svanheule.net> wrote:

...

> > > +       if (ret != 2)
> > > +               return -ENODEV;
> >
> > I would say -EINVAL, but -ENODEV is similarly okay.
>
> Any specific reason you think EINVAL is more appropriate than ENODEV?

My logic is that the initial values (from resource provider) are incorrect.
But as I said, I'm fine with either.

...

> > > +       int err;
> >
> > ret or err? Be consistent across a single driver.
>
> I had first used 'err' for both fwnode_property_count_u32() and
> fwnode_property_read_u32_array(). The former returns "actual count or error
> code", while the latter is only "error code". And I found it weird to read the
> code as "does error code equal 2", if I used 'err' as variable name.
>
> I've split this up:
>  * addr_count for fwnode_property_count_u32's result
>  * err for fwnode_property_read_u32_array's result
>
> Since addr_count is only used before err is touched, I guess the compiler will
> optimize this out anyway?

Usually we do this pattern (and it seems you missed the point, name of
variable is ret in some functions and err in the rest):

err /* ret */ = foo();
if (err < 0)
  return err;
count = err;

-- 
With Best Regards,
Andy Shevchenko