Re: [PATCH net-next 1/2] dt-bindings: net: xlnx,axi-ethernet: Add bindings for AXI 2.5G MAC

[Andrew Lunn <andrew@lunn.ch>]

On Mon, Nov 18, 2024 at 10:57:45AM -0500, Sean Anderson wrote:
> On 11/18/24 10:54, Maxime Chevallier wrote:
> > Hello,
> > 
> > On Mon, 18 Nov 2024 13:48:21 +0530
> > Suraj Gupta <suraj.gupta2@amd.com> wrote:
> > 
> >> AXI 1G/2.5G Ethernet subsystem supports 1G and 2.5G speeds. "max-speed"
> >> property is used to distinguish 1G and 2.5G MACs of AXI 1G/2.5G IP.
> >> max-speed is made a required property, and it breaks DT ABI but driver
> >> implementation ensures backward compatibility and assumes 1G when this
> >> property is absent.
> >> Modify existing bindings description for 2.5G MAC.
> > 
> > That may be a silly question, but as this is another version of the IP
> > that behaves differently than the 1G version, could you use instead a
> > dedicated compatible string for the 2.5G variant ?
> > 
> > As the current one is :
> > 
> > compatible = "xlnx,axi-ethernet-1.00.a";
> > 
> > it seems to already contain some version information.
> > 
> > But I might also be missing something :)
> 
> As it happens, this is not another version of the same IP but a
> different configuration. It's just that no one has bothered to add 2.5G
> support yet.

Do you mean 2.5G is a synthesis option? Or are you saying it has
always been able to do 2.5G, but nobody has added the needed code?

This is a pretty unusual use of max-speed, so i would like to fully
understand why it is being used before allowing it.

	Andrew