Re: phylink and an unusual PHY/SFP setup

[Andrew Lunn <andrew@lunn.ch>]

On Wed, May 27, 2026 at 10:19:18AM +0200, Michael Walle wrote:
> Hi,
> 
> I have a board with a rather unusual network link setup:
> 
>  MAC/PCS (fman) <-SerDes-> PHY (M88E1112) <-SerDes-> SFP
> 
> or even
> 
>  MAC/PCS (fman) <-SerDes-> PHY (M88E1112) <-SerDes-> Copper SFP with PHY

Such setups do exist already, but with a different PHY. The Marvel 10G
PHY is sometimes placed in the middle like this. And there are other
PHYs.

Take a look at

commit 35d1a5464b476aa98b7b76ce41bb4de748cebfc2
Author: Maxime Chevallier <maxime.chevallier@bootlin.com>
Date:   Thu Jan 8 09:00:35 2026 +0100

    net: phy: marvell10g: Support SFP through phy_port
    
    Convert the Marvell10G driver to use the generic SFP handling, through a
    dedicated .attach_port() handler to populate the port's supported
    interfaces.
    
    As the 88x3310 supports multiple MDI, the .attach_port() logic handles
    both SFP attach with 10GBaseR support, and support for the "regular"
    port that usually is a BaseT port.

Also, marvell-88x2222.c.

	Andrew