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From:   Bartosz Golaszewski <brgl@bgdev.pl>
Date:   Wed, 11 Oct 2023 17:03:10 +0200
Message-ID: <CAMRc=Mep2_u_JdGo_W1VsOR9ajscw49KA2gK7GN3K9j_rUEn_Q@mail.gmail.com>
Subject: Re: [PATCH 3/3] i2c: mux: gpio: don't fiddle with GPIOLIB internals
To:     Peter Rosin <peda@axentia.se>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        Andy Shevchenko <andy@kernel.org>,
        Peter Korsgaard <peter.korsgaard@barco.com>,
        linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-i2c@vger.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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On Wed, Oct 11, 2023 at 4:59=E2=80=AFPM Peter Rosin <peda@axentia.se> wrote=
:
>
> Hi!
>
> 2023-10-11 at 15:02, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > Use the relevant API functions to retrieve the address of the
> > underlying struct device instead of accessing GPIOLIB private structure=
s
> > manually.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > ---
> >  drivers/i2c/muxes/i2c-mux-gpio.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-m=
ux-gpio.c
> > index 5d5cbe0130cd..48a872a8196b 100644
> > --- a/drivers/i2c/muxes/i2c-mux-gpio.c
> > +++ b/drivers/i2c/muxes/i2c-mux-gpio.c
> > @@ -14,8 +14,7 @@
> >  #include <linux/slab.h>
> >  #include <linux/bits.h>
> >  #include <linux/gpio/consumer.h>
> > -/* FIXME: stop poking around inside gpiolib */
> > -#include "../../gpio/gpiolib.h"
> > +#include <linux/gpio/driver.h>
> >
> >  struct gpiomux {
> >       struct i2c_mux_gpio_platform_data data;
> > @@ -176,7 +175,8 @@ static int i2c_mux_gpio_probe(struct platform_devic=
e *pdev)
> >       }
> >
> >       for (i =3D 0; i < ngpios; i++) {
> > -             struct device *gpio_dev;
> > +             struct gpio_device *gdev;
> > +             struct device *dev;
> >               struct gpio_desc *gpiod;
> >               enum gpiod_flags flag;
> >
> > @@ -195,9 +195,9 @@ static int i2c_mux_gpio_probe(struct platform_devic=
e *pdev)
> >               if (!muxc->mux_locked)
> >                       continue;
> >
> > -             /* FIXME: find a proper way to access the GPIO device */
> > -             gpio_dev =3D &gpiod->gdev->dev;
> > -             muxc->mux_locked =3D i2c_root_adapter(gpio_dev) =3D=3D ro=
ot;
> > +             gdev =3D gpiod_to_gpio_device(gpiod);
> > +             dev =3D gpio_device_to_device(gdev);
> > +             muxc->mux_locked =3D i2c_root_adapter(dev) =3D=3D root;
> >       }
> >
> >       if (muxc->mux_locked)
>
> Very nice to see that wart gone! The only small question I have
> is if these helpers are needed elsewhere, or if a more "direct"
> gpiod_to_device() would have been sufficient? That said, I have
> zero problem with this new code as-is, and that detail is of
> course squarely in gpio-land.
>
> Acked-by: Peter Rosin <peda@axentia.se>

gpiod_to_gpio_device() will be used in at least 10 other places. I
haven't identified any other potential user for
gpio_device_to_device() yet but I haven't looked hard yet either.

Bart

>
> Cheers,
> Peter