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

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Message-ID: <CAMRc=MfVPO292xmnXBWJzWuhNADA_u1yvpJ4kkK8TgZyQgaP+A@mail.gmail.com>
Date: Fri, 17 Oct 2025 13:09:44 +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 12:48 PM Wolfram Sang
<wsa+renesas@...g-engineering.com> wrote:
>
>
> > > Interesting topic. In fact, I think we should make RESET_GPIO bool. I
> > > think the fallback mechanism of the core should work without any module
> > > loading infrastructure. It should be there whenever possible.
> > >
> >
> > You have not said *why*. How is this different from any other device
> > whose driver is only loaded when actually needed?
>
> ? I just did that, but let me repeat:
>
> 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 might add that module loading infrastructure might be broken in
> userspace. Been there. Also, some drivers might need their reset early?
>

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.

> Looking more into it, I can't find any 'request_module'. Am I
> overlooking something? The fallback feature is only present if the user
> loads the driver manually? If that is true, it would make it rather
> useless IMHO because consumer drivers cannot rely on it. I must be
> missing something...
>

The reset-gpio driver has a MODULE_DEVICE_TABLE().

Bart