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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Mon, 19 Dec 2022 14:50:36 +0100
Message-ID: <CAMuHMdW_QuBUUypyrAbLqWPdZ81bWeYDyPbBf=2KmDht1X44bA@mail.gmail.com>
Subject: Re: [PATCH RFC 1/5] dt-bindings: interrupt-controller:
 renesas,rzg2l-irqc: Document RZ/G2UL SoC
To:     "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Magnus Damm <magnus.damm@gmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        linux-gpio@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Biju Das <biju.das.jz@bp.renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
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Hi Prabhakar,

On Mon, Dec 19, 2022 at 1:57 PM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:
> On Fri, Nov 18, 2022 at 12:29 PM Lad, Prabhakar
> <prabhakar.csengg@gmail.com> wrote:
> > On Thu, Nov 17, 2022 at 10:54 AM Geert Uytterhoeven
> > <geert@linux-m68k.org> wrote:
> > > On Mon, Nov 7, 2022 at 6:53 PM Prabhakar <prabhakar.csengg@gmail.com> wrote:
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > >
> > > > Document RZ/G2UL (R9A07G043) IRQC bindings. The RZ/G2UL IRQC block is
> > > > identical to one found on the RZ/G2L SoC. No driver changes are
> > > > required as generic compatible string "renesas,rzg2l-irqc" will be
> > > > used as a fallback.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

> > > > Note, renesas,r9a07g043u-irqc is added we have slight difference's compared to RZ/Five
> > > > - G2UL IRQCHIP (hierarchical IRQ domain) -> GIC where as on RZ/Five we have PLIC (chained interrupt
> > > > domain) -> RISCV INTC
> > >
> > > I think this difference is purely a software difference, and abstracted
> > > in DTS through the interrupt hierarchy.
> > > Does it have any impact on the bindings?
> > >
> > > > - On the RZ/Five we have additional registers for IRQC block
> > >
> > > Indeed, the NMI/IRQ/TINT "Interruput" Mask Control Registers, thus
> > > warranting separate compatible values.
> > >
> > > > - On the RZ/Five we have BUS_ERR_INT which needs to be handled by IRQC
> > >
> > > Can you please elaborate? I may have missed something, but to me it
> > > looks like that is exactly the same on RZ/G2UL and on RZ/Five.
> > >
> > Now that we have to update the binding doc with the BUS_ERR_INT too,
> > do you think it would make sense to add interrupt-names too?

> Gentle ping.

Thanks for the ping, I had missed you were waiting on input from me.
Sorry for that...

As there are three different groups of parent interrupts, adding
interrupt-names makes sense.  However, as this binding is already
in active use since v6.1, you probably need to keep on supporting the
ack of interrupt-names.  Or do you think there are no real users yet,
and we can drop support for that?

> > BUS_ERR_INT will have to be handled IRQC itself (i.e. IRQC will
> > register a handler for it).

Do you mean you will need a fourth parent type for that?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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