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SubjectRe: [PATCH v3 1/7] ARM i.MX6q: remove PHY fixup for KSZ9031
On Tue, May 11, 2021 at 06:37:29AM +0200, Oleksij Rempel wrote:
> Starting with:
>
> bcf3440c6dd7 ("net: phy: micrel: add phy-mode support for the KSZ9031 PHY")
>
> the micrel phy driver started respecting phy-mode for the KSZ9031 PHY.
> At least with kernel v5.8 configuration provided by this fixup was
> overwritten by the micrel driver.
>
> This fixup was providing following configuration:
>
> RX path: 2.58ns delay
> rx -0.42 (left shift) + rx_clk +0.96ns (right shift) =
> 1,38 + 1,2 internal RX delay = 2.58ns
> TX path: 0.96ns delay
> tx (no delay) + tx_clk 0.96ns (right shift) = 0.96ns
>
> This configuration is outside of the recommended RGMII clock skew delays
> and about in the middle of: rgmii-idrx and rgmii-id
>
> Since most embedded systems do not have enough place to introduce
> significant clock skew, rgmii-id is the way to go.
>
> In case this patch breaks network functionality on your system, build
> kernel with enabled MICREL_PHY. If it is still not working then try
> following device tree options:
> 1. Set (or change) phy-mode in DT to:
> phy-mode = "rgmii-id";
> This actives internal delay for both RX and TX.
> 1. Set (or change) phy-mode in DT to:
> phy-mode = "rgmii-idrx";
> This actives internal delay for RX only.
> 3. Use following DT properties:
> phy-mode = "rgmii";
> txen-skew-psec = <0>;
> rxdv-skew-psec = <0>;
> rxd0-skew-psec = <0>;
> rxd1-skew-psec = <0>;
> rxd2-skew-psec = <0>;
> rxd3-skew-psec = <0>;
> rxc-skew-psec = <1860>;
> txc-skew-psec = <1860>;
> This activates the internal delays for RX and TX, with the value as
> the fixup that is removed in this patch.
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Andrew

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