Re: [PATCH v3 net-next 12/14] dt-bindings: net: dsa: ocelot: add ocelot-ext documentation

[Colin Foster <colin.foster@in-advantage.com>]

On Tue, Sep 27, 2022 at 11:26:00PM +0300, Vladimir Oltean wrote:
> On Sun, Sep 25, 2022 at 05:29:26PM -0700, Colin Foster wrote:
> > ---
> > +      - phy-mode = "internal": on ports 0, 1, 2, 3
> 
> More PHY interface types are supported. Please document them all.
> It doesn't matter what the driver supports. Drivers and device tree
> blobs should be able to have different lifetimes. A driver which doesn't
> support the SERDES ports should work with a device tree that defines
> them, and a driver that supports the SERDES ports should work with a
> device tree that doesn't.

This will change my patch a little bit then. I didn't undersand this
requirement.

My current device tree has all 8 ethernet ports populated. ocelot_ext
believes "all these port modes are accepted" by way of a fully-populated
vsc7512_port_modes[] array.

As a result, when I'm testing, swp4 through swp7 all enumerate as
devices, though they don't actually function. It isn't until serdes /
phylink / pcs / pll5 come along that they become functional ports.

I doubt this is desired. Though if I'm using the a new macro
OCELOT_PORT_MODE_NONE, felix.c stops after felix_validate_phy_mode.

I think the only thing I can do is to allow felix to ignore invalid phy
modes on some ports (which might be desired) and continue on with the
most it can do. That seems like a potential improvement to the felix
driver...

The other option is to allow the ports to enumerate, but leave them
non-functional. This is how my system currently acts, but as I said, I
bet it would be confusing to any user.

Thoughts?