linux-kernel - Re: [PATCH 5/5] arm64: dts: renesas: rzg2l-smarc-som: Add PHY interrupt support for ETH{0/1}

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Message-ID: <CA+V-a8uNZ8T6m+nav=UXTFcwtW8o_2dGE2QFMvkhwcUU=Ka42Q@mail.gmail.com>
Date:   Thu, 21 Jul 2022 12:54:41 +0100
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Magnus Damm <magnus.damm@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Biju Das <biju.das.jz@...renesas.com>
Subject: Re: [PATCH 5/5] arm64: dts: renesas: rzg2l-smarc-som: Add PHY
 interrupt support for ETH{0/1}

Hi Geert,

On Thu, Jul 21, 2022 at 12:43 PM Geert Uytterhoeven
<geert@...ux-m68k.org> wrote:
>
> Hi Prabhakar,
>
> On Thu, Jul 21, 2022 at 1:07 PM Lad, Prabhakar
> <prabhakar.csengg@...il.com> wrote:
> > On Thu, Jul 21, 2022 at 11:47 AM Geert Uytterhoeven
> > <geert@...ux-m68k.org> wrote:
> > > On Mon, Jul 18, 2022 at 9:57 PM Lad Prabhakar
> > > <prabhakar.mahadev-lad.rj@...renesas.com> wrote:
> > > > The PHY interrupt (INT_N) pin is connected to IRQ2 and IRQ3 for ETH0
> > > > and ETH1 respectively.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > >
> > > Thanks for your patch!
> > >
> > > > --- a/arch/arm64/boot/dts/renesas/rzg2l-smarc-som.dtsi
> > > > +++ b/arch/arm64/boot/dts/renesas/rzg2l-smarc-som.dtsi
> > > > @@ -94,6 +94,8 @@ phy0: ethernet-phy@7 {
> > > >                 compatible = "ethernet-phy-id0022.1640",
> > > >                              "ethernet-phy-ieee802.3-c22";
> > > >                 reg = <7>;
> > > > +               interrupt-parent = <&irqc>;
> > > > +               interrupts = <3 IRQ_TYPE_LEVEL_LOW>;
> > >
> > > 2?
> > >
> > IRQ2 = SPI 3, the driver expects the SPI number and is used as index
> > [0] to map the interrupt in the GIC.
> >
> > [0] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/irqchip/irq-renesas-rzg2l.c?h=next-20220720#n291
>
> Using the SPI number sounds strange to me, as the consumer
> (Ethernet PHY) is linked to the IRQC, not to the GIC directly.
>
Right, are you suggesting that I tweak the driver? The other problem
is how do we differentiate NMI and IRQ0? How about we add macros for
IRQ0-7 and use them in the DTS?

> > > "The first cell should contain external interrupt number (IRQ0-7)"
> > >
> > Probably I need to reword this to "The first cell should contain the
> > SPI number for IRQ0-7/NMI interrupt lines" ?
>
> Oh, so zero is the NMI?
> And 1-8 are IRQ0-7.
>
Yes that's right.

> All of this should be documented in the bindings.
>
> Probably you want to document the parent interrupts:
>   - First entry is NMI,
>   - Next 8 entries are IRQ0-7,
>   - Next 32 entries are TINT0-31.
> Currently it's a flat list.
>
Agreed, I will update that.

Cheers,
Prabhakar

> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds