linux-kernel - Re: [PATCH 2/2] gpio: aggregator: Use bitmap

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Message-ID: <CAHp75VenuB=up5wHm+BtkQPy_N6GuE7xvHJWq-e4Fricg1M7Vw@mail.gmail.com>
Date:   Wed, 24 Jun 2020 16:41:05 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] gpio: aggregator: Use bitmap_parselist() for parsing
 GPIO offsets

On Wed, Jun 24, 2020 at 3:16 PM Bartosz Golaszewski
<bgolaszewski@...libre.com> wrote:
>
> wt., 23 cze 2020 o 16:57 Geert Uytterhoeven <geert+renesas@...der.be>
> napisał(a):
> >
> > Replace the custom code to parse GPIO offsets and/or GPIO offset ranges
> > by a call to bitmap_parselist(), and an iteration over the returned bit
> > mask.
> >
> > This should have no impact on the format of the configuration parameters
> > written to the "new_device" virtual file in sysfs.
> >
> > Suggested-by: Andy Shevchenko <andy.shevchenko@...il.com>
> > Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> > ---
> > I'm not super happy with the mask[] array, which is on the stack.
> > But there is no real limit on the number of GPIO lines provided by a
> > single gpiochip, except for the global ARCH_NR_GPIOS.
>
> Why not allocate it with bitmap_zalloc() then?

I haven't got the original messages yet, so my thought is to actually
extract a helper from
gpiod_get_array_value_complex() or gpiod_set_array_value_complex() for
bitmap allocation.
But I didn't check if it's suitable here. So, bitmap_zalloc() would be helpful.

-- 
With Best Regards,
Andy Shevchenko