[PATCH net-next v4 4/4] net: ftgmac100: Add RGMII delay support for AST2600

From: Jacky Chou

Date: Tue Nov 11 2025 - 22:45:28 EST


Hi Andrew,

Thank you for your reply.

> > + /* Add a warning to notify the existed dts based on AST2600. It is
> > + * recommended to update the dts to add the rx/tx-internal-delay-ps to
> > + * specify the RGMII delay and we recommend using the "rgmii-id" for
> > + * phy-mode property to tell the PHY enables TX/RX internal delay and
> > + * add the corresponding rx/tx-internal-delay-ps properties.
> > + */
>
> I would not say that exactly. Normally you don't need rx/tx-internal-delay-ps. It
> is only requires for badly designed boards where the designer did not correctly
> balance the line lengths. So i would word this such that it is recommended to
> use "rgmii-id", and if necessary, add small "rx/tx-internal-delay-ps" values.
>

Agreed.
I will update this comment in next version.

> > + scu = syscon_regmap_lookup_by_phandle(np, "aspeed,scu");
> > + if (IS_ERR(scu)) {
> > + dev_err(dev, "failed to get aspeed,scu");
> > + return PTR_ERR(scu);
> > + }
>
> This is an optional property. If it does not exist, you have an old DT blob. It is
> not an error. So you need to do different things depending on what the error
> code is. If it does not exist, just return 0 and leave the hardware alone. If it is
> some other error report it, and abort the probe.
>

Based on this for next version, I want to move the "aspeed,scu" from dtsi to dts.
Change it to optional and accord it whether existed to decide it is old or new DT
blob.

Thanks,
Jacky