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From:   Fabio Estevam <festevam@gmail.com>
Date:   Wed, 9 Dec 2020 11:32:00 -0300
Message-ID: <CAOMZO5ChsXQk15o4aYf-mTmTVqhFTgKJUNbthnzGtWBhwj9zRw@mail.gmail.com>
Subject: Re: [PATCH v1] ARM: imx: mach-imx6ul: remove 14x14 EVK specific PHY fixup
To:     Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Sascha Hauer <kernel@pengutronix.de>,
        netdev <netdev@vger.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        NXP Linux Team <linux-imx@nxp.com>,
        David Jander <david@protonic.nl>,
        Russell King <linux@armlinux.org.uk>,
        Philippe Schenker <philippe.schenker@toradex.com>
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On Wed, Dec 9, 2020 at 9:21 AM Oleksij Rempel <o.rempel@pengutronix.de> wrote:
>
> Remove board specific PHY fixup introduced by commit:
>
> | 709bc0657fe6f9f5 ("ARM: imx6ul: add fec MAC refrence clock and phy fixup init")
>
> This fixup addresses boards with a specific configuration: a KSZ8081RNA
> PHY with attached clock source to XI (Pin 8) of the PHY equal to 50MHz.
>
> For the KSZ8081RND PHY, the meaning of the reg 0x1F bit 7 is different
> (compared to the KSZ8081RNA). A set bit means:
>
> - KSZ8081RNA: clock input to XI (Pin 8) is 50MHz for RMII
> - KSZ8081RND: clock input to XI (Pin 8) is 25MHz for RMII
>
> In other configurations, for example a KSZ8081RND PHY or a KSZ8081RNA
> with 25Mhz clock source, the PHY will glitch and stay in not recoverable
> state.
>
> It is not possible to detect the clock source frequency of the PHY. And
> it is not possible to automatically detect KSZ8081 PHY variant - both
> have same PHY ID. It is not possible to overwrite the fixup
> configuration by providing proper device tree description. The only way
> is to remove this fixup.
>
> If this patch breaks network functionality on your board, fix it by
> adding PHY node with following properties:
>
>         ethernet-phy@x {
>                 ...
>                 micrel,led-mode = <1>;
>                 clocks = <&clks IMX6UL_CLK_ENET_REF>;
>                 clock-names = "rmii-ref";
>                 ...
>         };
>
> The board which was referred in the initial patch is already fixed.
> See: arch/arm/boot/dts/imx6ul-14x14-evk.dtsi
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

Reviewed-by: Fabio Estevam <festevam@gmail.com>