Re: [PATCH net-next v6 3/3] net: dsa: yt921x: Add support for Motorcomm YT921x

[Andrew Lunn]

> Port 10 is dedicated to the internal MCU. Although I could not use it,
> anyone familiar with the chips would know it's Port 10 that is neither
> internal nor external.

The mv88e639X family has an internal Z80 CPU and its own port on the
switch. You will see code like:

                .num_ports = 11,        /* 10 + Z80 */
                .num_internal_phys = 8,

It is considered external, in that there is no internal PHY attached
In theory you could list it in DT, to instantiate the port, and then i
guess bad things to happen :-(

The good thing about this is, if you actually try use both the Z80 and
DSA to manage the switch, bad things are going to happen anyway.

So i would say there is some flexibility here, given how other drivers
handle this.

	Andrew