Hi Andrew,
On Fri, Nov 03, 2023 at 01:35:46PM +0100, Andrew Lunn wrote:
> > + port@2 {
> > + reg = <2>;
> > + label = "cpu";
> > + ethernet = <&eqos>;
> > + /* 2ns rgmii-rxid is implemented on PCB.
> > + * Switch should add only rgmii-txid.
> > + */
>
> Its unusual to actually see that. Its even more unusual its only one
> clock line. Can you actually see it on the PCB?
Yes. I even made a delay calculation by measuring this trace on PCB,
just to make sure I see it correctly.
> > + phy-mode = "rgmii-txid";
> > + tx-internal-delay-ps = <2000>;
>
> Is this actually needed? rgmii-txid should add 2ns delay. Since this
> apparently works, i'm assuming setting tx-internal-delay-ps to 2ns
> does nothing, otherwise you would have a 4ns delay.
Without it the driver will complain:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/dsa/microchip/ksz_common.c?h=v6.6#n3496
but it works as expected.
Regards,
Oleksij
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