linux-kernel - Re: [PATCH 1/3] gpio: tqmx86: really make IRQ optional

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Date:   Wed, 31 Mar 2021 17:03:10 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Matthias Schiffer <matthias.schiffer@...tq-group.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Lee Jones <lee.jones@...aro.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] gpio: tqmx86: really make IRQ optional

On Wed, Mar 31, 2021 at 4:36 PM Matthias Schiffer
<matthias.schiffer@...tq-group.com> wrote:
>
> 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@...tq-group.com> wrote:
> > > On Wed, 2021-03-31 at 15:29 +0300, Andy Shevchenko wrote:

...

> > > 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.

Ah, okay, that's something I haven't paid attention to.

So the root cause of the your case is platform_get_irq_optional|()
return code. I'm wondering why it can't return 0 instead of absent
IRQ? Perhaps you need to fix it instead of lurking into each caller.

-- 
With Best Regards,
Andy Shevchenko