linux-kernel - Re: [PATCH v4 3/7] gpio: gpiolib: Add ngirq member to struct gpio_irq

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Date:   Mon, 23 May 2022 18:27:01 +0100
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Marc Zyngier <maz@...nel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Thomas Gleixner <tglx@...utronix.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        linux-tegra <linux-tegra@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        Phil Edworthy <phil.edworthy@...esas.com>,
        Biju Das <biju.das.jz@...renesas.com>
Subject: Re: [PATCH v4 3/7] gpio: gpiolib: Add ngirq member to struct gpio_irq_chip

Hi Linus,

Thank you for the review.

On Thu, May 19, 2022 at 2:26 PM Linus Walleij <linus.walleij@...aro.org> wrote:
>
> On Wed, May 18, 2022 at 9:30 PM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@...renesas.com> wrote:
>
> > Supported GPIO IRQs by the chip is not always equal to the number of GPIO
> > pins. For example on Renesas RZ/G2L SoC where it has GPIO0-122 pins but at
> > a given point a maximum of only 32 GPIO pins can be used as IRQ lines in
> > the IRQC domain.
> >
> > This patch adds ngirq member to struct gpio_irq_chip and passes this as a
> > size to irq_domain_create_hierarchy()/irq_domain_create_simple() if it is
> > being set in the driver otherwise fallbacks to using ngpio.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> NAK
>
> As pointed out this is a property of the hardware and thus you should
> derive this property of the hardware from the compatible string.
>
> For example by passing per-variant .data in struct of_device_id.
>
> Unique hardware properties means unique hardware means it should
> have a unique compatible string. Otherwise something is wrong
> with the compatibles.
>
Agreed, I will drop this.

Cheers,
Prabhakar