linux-kernel - Re: [PATCH v2 21/23] gpio: protect the pointer to gpio_chip in gpio

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Message-ID: <CAMRc=MdoGQZKM37kk=j6NpdkUUjDvs3-8YeiZVQO2EpPHRZ7Uw@mail.gmail.com>
Date: Mon, 5 Feb 2024 20:36:39 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, Kent Gibson <warthog618@...il.com>, 
	Alex Elder <elder@...aro.org>, Geert Uytterhoeven <geert+renesas@...der.be>, 
	"Paul E . McKenney" <paulmck@...nel.org>, Wolfram Sang <wsa@...-dreams.de>, linux-gpio@...r.kernel.org, 
	linux-kernel@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH v2 21/23] gpio: protect the pointer to gpio_chip in
 gpio_device with SRCU

On Mon, Feb 5, 2024 at 1:31 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>

[snip]

>
> >  int gpiod_get_direction(struct gpio_desc *desc)
> >  {
> > -     struct gpio_chip *gc;
> >       unsigned long flags;
> >       unsigned int offset;
> >       int ret;
> >
> > -     gc = gpiod_to_chip(desc);
> > +     if (!desc)
> > +             /* Sane default is INPUT. */
> > +             return 1;
>
> Hmm... I can't imagine how this value may anyhow be used / useful.
>

What else would you return for an optional (NULL) GPIO?

Bart

[snip]