Re: [PATCH v2 21/23] gpio: protect the pointer to gpio_chip in gpio_device with SRCU

[Andy Shevchenko]

On Mon, Feb 05, 2024 at 08:36:39PM +0100, Bartosz Golaszewski wrote:
> On Mon, Feb 5, 2024 at 1:31 PM Andy Shevchenko
> <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:

..

> >
> > >  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?

An error. If somebody asks for direction of the non-existing GPIO, there is no
(valid) answer for that.

-- 
With Best Regards,
Andy Shevchenko