linux-kernel - Re: [PATCH v2 2/2] reset: always include RESET

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Message-ID: <CAMRc=MdWS2OSeJAkTRnAFMtXcVukwQ=JAWwJ3OHxogmgZnan6g@mail.gmail.com>
Date: Fri, 17 Oct 2025 19:02:38 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>
Cc: Geert Uytterhoeven <geert@...ux-m68k.org>, linux-renesas-soc@...r.kernel.org, 
	Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>, 
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>, linux-kernel@...r.kernel.org, 
	Philipp Zabel <p.zabel@...gutronix.de>
Subject: Re: [PATCH v2 2/2] reset: always include RESET_GPIO driver if possible

On Fri, Oct 17, 2025 at 1:25 PM Wolfram Sang
<wsa+renesas@...g-engineering.com> wrote:
>
>
> > > I think the fallback mechanism of the core should work without any
> > > module loading infrastructure. It should be there whenever possible.
> > >
> >
> > It's not really a fallback, is it? This is the path we'll always take
> > if the driver requests a reset control on a firmware node which has a
> > reset-gpios property. If the driver goes with the gpiod API, it will
> > get a regular descriptor. It's deterministic enough to not warrant the
> > term "fallback".
>
> I dunno for how many drivers this is really applicable, but I really
> liked the cleanup of the pca954x driver. Don't handle GPIOs internally,
> just get a reset, and it might be a GPIO. I think it is very useful and
> I would like to see it wherever possible.
>
> We could now make these drivers depend on RESET_GPIO. This would make
> sense in a way but is uncomfortable for the user who has not RESET_GPIO
> enabled before. The driver would just disappear because of unmet
> dependencies. Yes, this can happen all the time because we always find
> new dependencies and describe them. I just hoped it could be avoided in
> this case.
>
> > Then I believe the platform's config should make sure the driver is
> > built-in. I don't think it makes sense to just cram it into the kernel
> > image for the few users it currently has.
>
> For Morimoto-san, the PCA954x update resulted in a regression. It is
> worth thinking how to avoid that. The driver is so small, I wouldn't
> mind the extra space if it saves users from disappearing devices. But
> mileages vary...
>

It's up to Philipp but I'd personally go with "default m if GPIOLIB".

Bartosz