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

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Message-ID: <20251015134839.1b71fe28@bootlin.com>
Date: Wed, 15 Oct 2025 13:48:39 +0200
From: Herve Codina <herve.codina@...tlin.com>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Hoan Tran
 <hoan@...amperecomputing.com>, Linus Walleij <linus.walleij@...aro.org>,
 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 Wolfram,

On Wed, 24 Sep 2025 20:41:20 +0200
Wolfram Sang <wsa+renesas@...g-engineering.com> wrote:

> Hi Herve,
> 
> On Mon, Sep 22, 2025 at 05:26:38PM +0200, Herve Codina (Schneider Electric) wrote:
> > On the Renesas RZ/N1 SoC, GPIOs can generate interruptions. Those
> > interruption lines are multiplexed by the GPIO Interrupt Multiplexer in
> > order to map 32 * 3 GPIO interrupt lines to 8 GIC interrupt lines.
> > 
> > The GPIO interrupt multiplexer IP does nothing but select 8 GPIO
> > IRQ lines out of the 96 available to wire them to the GIC input lines.
> > 
> > Signed-off-by: Herve Codina (Schneider Electric) <herve.codina@...tlin.com>  
> 
> Thanks for improving the driver and removing the requirement of a fixed
> ordering!
> 
> > +static u32 rzn1_irqmux_output_lines[] = {  
> 
> const?

Yes, will be added in the next iteration.

> 
> > +	103, 104, 105, 106, 107, 108, 109, 110
> > +};  
> 
> ...
> 
> > +	for (i = 0; i < ARRAY_SIZE(rzn1_irqmux_output_lines); i++) {
> > +		if (parent_args->args[1] == rzn1_irqmux_output_lines[i])
> > +			return i;
> > +	}  
> 
> Do we want a check here if the index has already been used in cases of
> an improper 'interrupt-map'? I'd think it would be nice to have but I
> would also not really require it.

Agree, it will be a good improvement.

I will add this check in the next iteration.

> 
> ...
> 
> > +	ret = rzn1_irqmux_setup(dev, np, regs);
> > +	if (ret)
> > +		return dev_err_probe(dev, ret, "failed to setup mux\n");
> > +
> > +	return 0;  
> 
> Maybe just
> 
> 	return rzn1_irqmux_setup(dev, np, regs);
> 
> The driver core will report a failed probe already.

Yes

> 
> It still works, so:
> 
> Tested-by: Wolfram Sang <wsa+renesas@...g-engineering.com>

With update planned (new check for already been used indexes), a
re-test will be probably needed.

Best regards,
Hervé