linux-kernel - Re: [PATCH 6/6] nvmem: increase the reference count of a gpio passed over config

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Date:   Mon, 17 Feb 2020 23:09:33 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        Khouloud Touil <ktouil@...libre.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH 6/6] nvmem: increase the reference count of a gpio passed
 over config

pon., 17 lut 2020 o 22:13 Geert Uytterhoeven <geert@...ux-m68k.org> napisał(a):
>
> Hi Bartosz,
>
> On Mon, Feb 17, 2020 at 8:56 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:
> > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> >
> > We can obtain the write-protect GPIO in nvmem_register() by requesting
> > it ourselves or by storing the gpio_desc passed in nvmem_config. In the
> > latter case we need to increase the reference count so that it gets
> > freed correctly.
> >
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
>
> Thanks for your patch!
>
> > --- a/drivers/nvmem/core.c
> > +++ b/drivers/nvmem/core.c
> > @@ -349,11 +349,13 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
> >                 return ERR_PTR(rval);
> >         }
> >
> > -       if (config->wp_gpio)
> > +       if (config->wp_gpio) {
> >                 nvmem->wp_gpio = config->wp_gpio;
> > -       else
> > +               gpiod_ref(config->wp_gpio);
>
> If gpiod_ref() would return the passed GPIO, or an error code, you could write
>
>         nvmem->wp_gpio = gpiod_ref(config->wp_gpio);
>

Yes, makes perfect sense - v2 coming up tomorrow.

Bart