linux-kernel - Re: [PATCH v6 4/6] reset: Instantiate reset GPIO controller for shared reset-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: <7a65b551-817d-4f51-8eb9-bd8b2f93dcba@sirena.org.uk>
Date: Wed, 31 Jan 2024 13:31:27 +0000
From: Mark Brown <broonie@...nel.org>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: Bartosz Golaszewski <brgl@...ev.pl>,
	Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
	Banajit Goswami <bgoswami@...cinc.com>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Rob Herring <robh+dt@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Frank Rowand <frowand.list@...il.com>,
	Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
	alsa-devel@...a-project.org, linux-arm-msm@...r.kernel.org,
	linux-sound@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Chris Packham <chris.packham@...iedtelesis.co.nz>,
	Sean Anderson <sean.anderson@...o.com>
Subject: Re: [PATCH v6 4/6] reset: Instantiate reset GPIO controller for
 shared reset-gpios

On Wed, Jan 31, 2024 at 02:17:54PM +0100, Linus Walleij wrote:
> On Wed, Jan 31, 2024 at 10:37 AM Bartosz Golaszewski <brgl@...ev.pl> wrote:

> > This is a different problem: it supports many users enabling the same
> > GPIO (in Krzysztof's patch it's one but could be more if needed) but -
> > unlike the broken NONEXCLUSIVE GPIOs in GPIOLIB - it counts the number
> > of users and doesn't disable the GPIO for as long as there's at least
> > one.

> I don't know if the NONEXCLUSIVE stuff is broken, if you mean reference
> counting isn't working on them, then that is by design because they were
> invented for regulators and such use cases that do their own reference
> counting. It's also used for hacks where people need to look up a desc in
> a second spot, (perhaps we can fix those better).

Their own reference counting or whatever other coordination they want -
the deal is that users are responsible for their own coordination
whatever that might be.

> The NONEXCLUSIVE stuff was prompted by converting regulators to
> gpio descriptors, so it was for the greater good one can say. Or the
> lesser evil :( my judgement can be questioned here.

Right, previously we were working out if a GPIO was shared by looking at
the GPIO number but with descriptors we need to get the GPIO before we
can do anything with it, including figure out if it's shared.

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)