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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Tue, 8 Feb 2022 13:31:08 +0100
Message-ID: <CAK8P3a3owi7YWmq-tckD-C7NK5HaX+swGNW-QBkWQuQgVsVWrA@mail.gmail.com>
Subject: Re: [PATCH 2/3] i2c: sh_mobile: Use platform_get_irq_optional() to
 get the interrupt
To:     Sergei Shtylyov <sergei.shtylyov@gmail.com>
Cc:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        Rob Herring <robh+dt@kernel.org>,
        Nicolas Saenz Julienne <nsaenz@kernel.org>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Ray Jui <rjui@broadcom.com>,
        Scott Branden <sbranden@broadcom.com>,
        bcm-kernel-feedback-list <bcm-kernel-feedback-list@broadcom.com>,
        Chris Brandt <chris.brandt@renesas.com>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Linux I2C <linux-i2c@vger.kernel.org>,
        linux-rpi-kernel <linux-rpi-kernel@lists.infradead.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        Prabhakar <prabhakar.csengg@gmail.com>,
        Linux-sh list <linux-sh@vger.kernel.org>
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On Mon, Dec 20, 2021 at 12:53 PM Sergei Shtylyov
<sergei.shtylyov@gmail.com> wrote:
> On 20.12.2021 13:17, Geert Uytterhoeven wrote:
>
> > I might have missed something, but it seems the only user of IRQ 0 on
> > SuperH is smsc911x Ethernet in arch/sh/boards/board-apsh4a3a.c and
> > arch/sh/boards/board-apsh4ad0a.c, which use evt2irq(0x200).
> > These should have been seeing the "0 is an invalid IRQ number"
> > warning splat since it was introduced in commit a85a6c86c25be2d2
> > ("driver core: platform: Clarify that IRQ 0 is invalid"). Or not:
>
>     Warning or no warning, 0 is still returned. :-/
>     My attempt to put an end to this has stuck waiting a review from the IRQ
> people...

I had another look at this after you asked about it on IRC. I don't
know much SH assembly, but I suspect IRQ 0 has not been delivered
since 2009 after 1e1030dccb10 ("sh: nmi_debug support."). On a
related note, CONFIG_INTC_BALANCING was broken in 2be6bb0c79c7
("sh: intc: Split up the INTC code.") by inadvertently removing the Kconfig
symbol.

        Arnd