linux-kernel - Re: [PATCH v4 7/8] soc: renesas: Add support for Renesas RZ/N1 GPIO Interrupt Multiplexer

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: <aO5ekPxeg7tdFlHi@shikoro>
Date: Tue, 14 Oct 2025 16:30:40 +0200
From: Wolfram Sang <wsa+renesas@...g-engineering.com>
To: Linus Walleij <linus.walleij@...aro.org>
Cc: Herve Codina <herve.codina@...tlin.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Hoan Tran <hoan@...amperecomputing.com>,
	Bartosz Golaszewski <brgl@...ev.pl>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	Saravana Kannan <saravanak@...gle.com>,
	Serge Semin <fancer.lancer@...il.com>,
	Phil Edworthy <phil.edworthy@...esas.com>,
	linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
	Pascal Eberhard <pascal.eberhard@...com>,
	Miquel Raynal <miquel.raynal@...tlin.com>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v4 7/8] soc: renesas: Add support for Renesas RZ/N1 GPIO
 Interrupt Multiplexer

Hi Linus,

giving some details about the HW until Herve can return to this topic.

> Are these IRQ lines ever muxed for anything else than
> GPIO? In that case go ahead with this solution, I guess.
> But the title of your patch seems to suggest it is
> only used by GPIO.

True, it only muxes 96 GPIOs to the 8 available irqs.

> If it is only used for GPIO, why make it a separate
> driver instead of just putting the muxing into the
> GPIO driver?

Because the HW design kind of suggests it, I'd think. The GPIO
controller is a standard Synopsis one ("snps,dw-apb-gpio") without any
extras. The GPIOMUX (which is extra) is according to the docs part of
the system controller with a dedicated set of registers. Luckily,
self-contained and not mangled with other functionality.

I am just stating where this comes from. I haven't looked into the
details of your suggestion. It may or may not make sense to add this to
the Synopsis driver with a dedicated compatible for RZ/N1D. I'll leave
this for Herve, though.

Happy hacking,

   Wolfram

Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)