linux-kernel - Re: [PATCH RFC 0/9] gpio: improve support for shared GPIOs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAMRc=McGuNX42k_HdV20zW+buACBTmTZEHWgS-ddRYsvnfwDSg@mail.gmail.com>
Date: Tue, 21 Oct 2025 14:22:46 +0200
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Manivannan Sadhasivam <mani@...nel.org>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>, Kees Cook <kees@...nel.org>, 
	Mika Westerberg <westeri@...nel.org>, Andrew Morton <akpm@...ux-foundation.org>, 
	Linus Walleij <linus.walleij@...aro.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Saravana Kannan <saravanak@...gle.com>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
	Andy Shevchenko <andy@...nel.org>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
	Srinivas Kandagatla <srini@...nel.org>, Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, 
	Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>, linux-hardening@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-sound@...r.kernel.org, 
	linux-arm-msm@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH RFC 0/9] gpio: improve support for shared GPIOs

On Tue, Oct 21, 2025 at 2:20 PM Manivannan Sadhasivam <mani@...nel.org> wrote:
>
> >
> > And with the implementation this series proposes it would mean that
> > the perst signal will go high after the first endpoint pwrctl driver
> > sets it to high and only go down once the last driver sets it to low.
> > The only thing I'm not sure about is the synchronization between the
> > endpoints - how do we wait for all of them to be powered-up before
> > calling the last gpiod_set_value()?
> >
>
> That will be handled by the pwrctrl core. Not today, but in the coming days.
>

But is this the right approach or are you doing it this way *because*
there's no support for enable-counted GPIOs as of yet?

Bart