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Message-ID: <38b1191ce594d9fefe9e0e98b3fa8ca0a23ee3ea.camel@ew.tq-group.com>
Subject: Re: [PATCH 1/3] gpio: tqmx86: really make IRQ optional
From:   Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Lee Jones <lee.jones@linaro.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Date:   Wed, 31 Mar 2021 15:36:22 +0200
In-Reply-To: <CAHp75VfVCTj170S_4Lh9JyDYFfUQLjTtnU=O-iXgUVXcycLxwg@mail.gmail.com>
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         <CAHp75Vcc3CNXguMK-ZhRfvfjVBQBbcGEYK_+WQAmb_Sw5-Derw@mail.gmail.com>
         <4c143c8ee65fe52840ccbb4e1b422b6e473563d9.camel@ew.tq-group.com>
         <CAHp75VfVCTj170S_4Lh9JyDYFfUQLjTtnU=O-iXgUVXcycLxwg@mail.gmail.com>
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On Wed, 2021-03-31 at 15:39 +0300, Andy Shevchenko wrote:
> On Wed, Mar 31, 2021 at 3:37 PM Matthias Schiffer
> <matthias.schiffer@ew.tq-group.com> wrote:
> > On Wed, 2021-03-31 at 15:29 +0300, Andy Shevchenko wrote:
> > > On Wed, Mar 31, 2021 at 2:37 PM Matthias Schiffer
> > > <matthias.schiffer@ew.tq-group.com> wrote:
> 
> ...
> 
> > > > -       irq = platform_get_irq(pdev, 0);
> > > > -       if (irq < 0)
> > > > +       irq = platform_get_irq_optional(pdev, 0);
> > > > +       if (irq < 0 && irq != -ENXIO)
> > > >                 return irq;
> > > 
> > > This is a dead code now. I suggest you to do the opposite, i.e.
> > > if (irq < 0)
> > >   irq = 0;
> > 
> > I don't understand which part of the code is dead now. I assume the
> > `return irq` case is still useful for unexpected errors, or things like
> > EPROBE_DEFER? I'm not sure if EPROBE_DEFER is relevant for this driver,
> > but just ignoring the error code completely doesn't seem right to me.
> 
> platform_get_irq() AFAIK won't ever return such a code.
> So, basically your conditional is always false.
> 
> I would like to see the code path which makes my comment wrong.
> 

EPROBE_DEFER appears a few times in platform_get_irq_optional()
(drivers/base/platform.c), but it's possible that this is only relevant
for OF-based platforms and not x86.