Re: [PATCH v3 1/5] pinctrl: renesas: gpio: isolate function gpiochip from parent fwnode

[Geert Uytterhoeven]

On Wed, 30 Sept 2026 at 06:58, Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> wrote:
> The sh-pfc driver registers two separate gpiochip instances: one for
> real GPIOs and another for function GPIOs. Since both share the same
> parent platform device, gpiolib's fallback logic causes both chips to
> share the same firmware node (fwnode).
>
> This causes ambiguity when using software nodes to describe GPIOs, as
> gpiolib may apply hogs meant for one chip to the other if they share the
> same node.
>
> Explicitly set gc->fwnode to ERR_PTR(-ENODEV) for the function GPIO
> chip. This satisfies gpiolib's check for an existing fwnode and prevents
> it from falling back to the parent device's node, while ensuring that no
> actual properties or hogs are found on the function chip unless
> explicitly assigned later.
>
> Assisted-by: LLM
> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>

> --- a/drivers/pinctrl/renesas/gpio.c
> +++ b/drivers/pinctrl/renesas/gpio.c
> @@ -278,6 +278,12 @@ static int gpio_function_setup(struct sh_pfc_chip *chip)

As this function is only used on SH:
Acked-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds