Re: [PATCH 3/8] arm64: dts: qcom: sa8775p: Add ethernet card for ride & ride-r3

[Mohd Ayaan Anwar <quic_mohdayaa@quicinc.com>]

On Wed, May 07, 2025 at 04:23:52PM +0200, Andrew Lunn wrote:
> > +&ethernet0 {
> > +	phy-handle = <&sgmii_phy0>;
> > +	phy-mode = "sgmii";
> > +
> > +	pinctrl-0 = <&ethernet0_default>;
> > +	pinctrl-names = "default";
> > +
> > +	snps,mtl-rx-config = <&mtl_rx_setup>;
> > +	snps,mtl-tx-config = <&mtl_tx_setup>;
> > +	snps,ps-speed = <1000>;
> 
> SGMII can only go up to 1000, so why is this property needed?
> 

That's true. This shouldn't be required.

> > +&ethernet0 {
> > +	phy-handle = <&hsgmii_phy0>;
> > +	phy-mode = "2500base-x";
> > +
> > +	pinctrl-0 = <&ethernet0_default>;
> > +	pinctrl-names = "default";
> > +
> > +	snps,mtl-rx-config = <&mtl_rx_setup>;
> > +	snps,mtl-tx-config = <&mtl_tx_setup>;
> > +	snps,ps-speed = <1000>;
> 
> This looks odd. 2500Base-X, yet 1000?
> 
> 	Andrew

Just to give some background, this board is using the infamous OCSGMII
mode. But you are correct, the "snps,ps-speed" property is not required
here. The qcom-ethqos driver is agnostic to it as the MAC speed is set
using PCS AN during mac_link_up:
stmmac_mac_link_up -> fix_mac_speed -> ethqos_configure_sgmii.

We will remove it in the next revision of [0]. I also noticed this
redundant property in a few other places and will submit separate
cleanup patches for those as well.

	Ayaan
---
[0] https://lore.kernel.org/all/20250826-lemans-evk-bu-v1-3-08016e0d3ce5@oss.qualcomm.com/