Re: [PATCH 3/6] gpio: TODO: remove the pinctrl integration task

[Linus Walleij]

On Fri, Mar 21, 2025 at 4:49 PM Bartosz Golaszewski <brgl@xxxxxxxx> wrote:

> From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
>
> While there are surely some arguments in favor of integrating the GPIO
> and pinctrl subsystems into one, I believe this is not the right
> approach.
>
> The GPIO subsystem uses intricate locking with SRCU to handle the fact
> that both consumers and providers may run in different contexts.
> Pin-controller drivers are always meant to run in process context. This
> alone is a huge obstacle to any attempt at integration as evident by
> many problems we already encountered during the hotplug rework.
>
> The current glue code is pretty minimal and for most part already allows
> GPIO controllers to query pinctrl about the information they need.
>
> I suggest to drop this task and keep the subsystems separate even if
> many pin-controllers implement GPIO functionality in addition to pin
> functions.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>

I used to get this push a lot in the past from users, that it should be
the same subsystem, but I haven't heard it much recently so I
guess they have finally given up on it.
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Yours,
Linus Walleij