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SubjectRe: [PATCH devicetree 1/3] ARM: dts: imx6qp-prtwd3: update RGMII delays for sja1105 switch
On Wed, Oct 20, 2021 at 02:36:11PM +0300, Vladimir Oltean wrote:
> In the new behavior, the sja1105 driver expects there to be explicit
> RGMII delays present on the fixed-link ports, otherwise it will complain
> that it falls back to legacy behavior, which is to apply RGMII delays
> incorrectly derived from the phy-mode string.
>
> In this case, the legacy behavior of the driver is to apply both RX and
> TX delays. To preserve that, add explicit 2 nanosecond delays, which are
> identical with what the driver used to add (a 90 degree phase shift).
> The delays from the phy-mode are ignored by new kernels (it's still
> RGMII as long as it's "rgmii*" something), and the explicit
> {rx,tx}-internal-delay-ps properties are ignored by old kernels, so the
> change works both ways.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>

> ---
> arch/arm/boot/dts/imx6qp-prtwd3.dts | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/arch/arm/boot/dts/imx6qp-prtwd3.dts b/arch/arm/boot/dts/imx6qp-prtwd3.dts
> index 7648e8a02000..cf6571cc4682 100644
> --- a/arch/arm/boot/dts/imx6qp-prtwd3.dts
> +++ b/arch/arm/boot/dts/imx6qp-prtwd3.dts
> @@ -178,6 +178,8 @@ port@4 {
> label = "cpu";
> ethernet = <&fec>;
> phy-mode = "rgmii-id";
> + rx-internal-delay-ps = <2000>;
> + tx-internal-delay-ps = <2000>;
>
> fixed-link {
> speed = <100>;
> --
> 2.25.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

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