Re: [PATCH v5 3/6] net: phy: at803x: add QCA8084 ethernet phy support

On Sat, Nov 18, 2023 at 02:27:51PM +0800, Luo Jie wrote:

Add qca8084 PHY support, which is four-port PHY with maximum
link capability 2.5G, the features of each port is almost same
as QCA8081 and slave seed config is not needed.

Three kind of interface modes supported by qca8084.
PHY_INTERFACE_MODE_10G_QXGMII, PHY_INTERFACE_MODE_2500BASEX and
PHY_INTERFACE_MODE_SGMII.

Sorry for joining the conversation late.

I'm trying to get my head around QXGMII. Let me describe what i think
is happening, and then you can correct me....

You have 4 MACs, probably in a switch. The MII interfaces from these
MACs go into a multiplexer, and out comes QXGMII? You then have a
SERDES interface out of the switch and into the PHY package. Inside
the PHY package there is a demultiplexor, giving you four MII
interfaces, one to each PHY in the package.

If you have the PHY SERDES running in 2500BaseX, you have a single
MAC, no mux/demux, and only one PHY is used? The other three are idle.
Same from SGMII?

So the interface mode QXGMII is a property of the package. It is not
really a property of one PHY. Having one PHY using QXGMII and another
SGMII does not work?

     Andrew