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

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Message-ID: <4c143c8ee65fe52840ccbb4e1b422b6e473563d9.camel@ew.tq-group.com>
Date:   Wed, 31 Mar 2021 14:36:59 +0200
From:   Matthias Schiffer <matthias.schiffer@...tq-group.com>
To:     Andy Shevchenko <andy.shevchenko@...il.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: (EXT) Re: [PATCH 1/3] gpio: tqmx86: really make IRQ optional

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@...tq-group.com> wrote:
> > 
> > The tqmx86 MFD driver was passing IRQ 0 for "no IRQ" in the past. This
> > causes warnings with newer kernels.
> > 
> > Prepare the gpio-tqmx86 driver for the fixed MFD driver by handling a
> > missing IRQ properly.
> 
> ...
> 
> > -       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.



> 
> In such a case below change is not required.
> 
> ...
> 
> > -       if (irq) {
> > +       if (irq > 0) {
> >                 struct irq_chip *irq_chip = &gpio->irq_chip;
> >                 u8 irq_status;
> 
>