linux-kernel - Re: [RFC v7 5/6] gpio: mpfs: pass gpio line number as irq data

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Message-ID: <CACRpkdYdxdLG8=_Xd7HLwQ5+pxwGw6Xte7=UNbknB8HR474bcQ@mail.gmail.com>
Date: Mon, 5 Aug 2024 10:11:09 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Conor Dooley <conor.dooley@...rochip.com>
Cc: linux-kernel@...r.kernel.org, conor@...nel.org, 
	Marc Zyngier <maz@...nel.org>, Daire McNamara <daire.mcnamara@...rochip.com>, 
	Bartosz Golaszewski <brgl@...ev.pl>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, 
	Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, 
	linux-riscv@...ts.infradead.org, linux-gpio@...r.kernel.org, 
	devicetree@...r.kernel.org
Subject: Re: [RFC v7 5/6] gpio: mpfs: pass gpio line number as irq data

Hi Conor,

thanks for your patch!

On Tue, Jul 23, 2024 at 1:28 PM Conor Dooley <conor.dooley@...rochip.com> wrote:

> Since the interrupt mux is going to provide us a 1:1 mapping for
> interrupts, and it is no longer correct to hit all of the set bits in
> the interrupt handler, store the GPIO that "owns" an interrupt in its
> data pointer, so that we can determine which bit to clear.
>
> Signed-off-by: Conor Dooley <conor.dooley@...rochip.com>

I don't quite get this, the irqchip of the GPIO is clearly hard-coded
hierarchical, then why don't you:

select IRQ_DOMAIN_HIERARCHY

And use e.g. girq->child_to_parent_hwirq() to handle the
hierarchy?

See drivers/gpio/gpio-ixp4xx.c for a simple example of a hierarchical
GPIO interrupt controller.

Yours,
Linus Walleij