linux-kernel - Re: [PATCH v1 1/1] gpiolib: Return label, if set, for IRQ only line

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Message-ID: <CAMRc=MeuAQgos+=GmYr0X+5Pi+foJaRNwuNM0D3b4-FwxoD2mg@mail.gmail.com>
Date: Thu, 9 May 2024 16:23:07 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>, Linus Walleij <linus.walleij@...aro.org>, 
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] gpiolib: Return label, if set, for IRQ only line

On Thu, May 9, 2024 at 3:58 PM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> Thu, May 09, 2024 at 03:15:05PM +0200, Bartosz Golaszewski kirjoitti:
> > On Wed, May 8, 2024 at 4:47 PM Andy Shevchenko
> > <andriy.shevchenko@...ux.intel.com> wrote:
> > >
> > > If line has been locked as IRQ without requesting,
> > > still check its label and return it, if not NULL.
> > >
> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > > ---
> > >  drivers/gpio/gpiolib.c | 12 ++++++------
> > >  1 file changed, 6 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> > > index db536ec9734d..1f1673552767 100644
> > > --- a/drivers/gpio/gpiolib.c
> > > +++ b/drivers/gpio/gpiolib.c
> > > @@ -105,16 +105,16 @@ const char *gpiod_get_label(struct gpio_desc *desc)
> > >         unsigned long flags;
> > >
> > >         flags = READ_ONCE(desc->flags);
> > > -       if (test_bit(FLAG_USED_AS_IRQ, &flags) &&
> > > -           !test_bit(FLAG_REQUESTED, &flags))
> > > -               return "interrupt";
> > > -
> > > -       if (!test_bit(FLAG_REQUESTED, &flags))
> > > -               return NULL;
> > >
> > >         label = srcu_dereference_check(desc->label, &desc->srcu,
> > >                                        srcu_read_lock_held(&desc->srcu));
> > >
> > > +       if (test_bit(FLAG_USED_AS_IRQ, &flags))
> > > +               return label->str ?: "interrupt";
> > > +
> > > +       if (!test_bit(FLAG_REQUESTED, &flags))
> > > +               return NULL;
> > > +
> > >         return label->str;
> > >  }
> >
> > What good would it be if gpiochip_dup_line_label() returns NULL for
> > unrequested lines anyway?
>
> Then it should be handled differently in those cases. So, consider it as
> a preparatory patch which doesn't change current behaviour.
>
> (Yes, I have some hack patches locally which do something useful, but they are
> not ready. In any case this one looks to me as a good cleanup on its own for
> the sake of readability of the code and reduced amount of checks.)
>

Fair enough but I would like to know what your bigger plan is before
picking this up.

Bart