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    SubjectRe: [PATCH 2/4] Revert "arm64: dts: renesas: Add compatible properties to AR8031 Ethernet PHYs"
    On Fri, Jan 6, 2023 at 8:28 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
    >
    > Hi Adam,
    >
    > CC Ethernet phy
    >
    > On Wed, Jan 4, 2023 at 3:12 PM Adam Ford <aford173@gmail.com> wrote:
    > > This reverts commit 18a2427146bf8a3da8fc7825051d6aadb9c2d8fb.
    > >
    > > Due to the part shortage, the AR8031 PHY was replaced with a
    > > Micrel KSZ9131. Hard-coding the ID of the PHY makes this new
    > > PHY non-operational. Since previous hardware had shipped,
    > > it's not as simple as just replacing the ID number as it would
    > > break the older hardware. Since the generic mode can correctly
    > > identify both versions of hardware, it seems safer to revert
    > > this patch.
    > >
    > > Signed-off-by: Adam Ford <aford173@gmail.com>
    >
    > Thanks for your patch!
    >
    > > --- a/arch/arm64/boot/dts/renesas/beacon-renesom-som.dtsi
    > > +++ b/arch/arm64/boot/dts/renesas/beacon-renesom-som.dtsi
    > > @@ -59,8 +59,6 @@ &avb {
    > > status = "okay";
    > >
    > > phy0: ethernet-phy@0 {
    > > - compatible = "ethernet-phy-id004d.d074",
    > > - "ethernet-phy-ieee802.3-c22";
    > > reg = <0>;
    > > interrupt-parent = <&gpio2>;
    > > interrupts = <11 IRQ_TYPE_LEVEL_LOW>;
    >
    > The next line:
    >
    > reset-gpios = <&gpio2 10 GPIO_ACTIVE_LOW>;
    >
    > Unfortunately, removing the compatible value will cause regressions
    > for kexec/kdump and for Ethernet driver unbind, as the PHY reset will
    > be asserted before starting the new kernel, or on driver unbind.
    > Due to a deficiency in the Ethernet PHY subsystem, the PHY will be
    > probed while the reset is still asserted, and thus fail probing[1].

    FWIW, the bootloader brings the device out of reset. Would it be
    sufficient to keep "ethernet-phy-ieee802.3-c22" and drop the
    hard-coded ID?

    thanks,

    adam
    >
    > Is there a (new) proper way to handle this?
    > Perhaps the issue has been fixed in the PHY subsystem meanwhile?
    >
    > Thanks!
    >
    > [1] https://lore.kernel.org/all/cover.1631174218.git.geert+renesas@glider.be
    >
    > 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

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