Re: [PATCH net-next 4/8] net: phylink: update supported_interfaces with modes from fwnode

On Thu, Nov 18, 2021 at 06:33:01PM +0100, Marek Behún wrote:

On Thu, 18 Nov 2021 17:08:10 +0000
"Russell King (Oracle)" [off-list ref] wrote:

quoted

I'm quite certain that as we try to develop phylink, such as adding
extra facilities like specifying the interface modes, we're going to
end up running into these kinds of problems that we can't solve, and
we are going to have to keep compatibility for the old ways of doing
stuff going for years to come - which is just going to get more and
more painful.

One way to move this forward would be to check compatible of the
corresponding MAC in this new function. If it belongs to an unconverted
driver, we can ensure the old behaviour. This would require to add a
comment to the driver saying "if you convert this, please drop the
exception in phylink_update_phy_modes()".

That could work when drivers pass the fwnode as the "device" node.
Some drivers don't do that, they pass a sub-node instead - such as
mvpp2. However, mvpp2 is of course up to date with all phylink
developments.

However, the same issue exists with DSA - the fwnode passed to
phylink doesn't have a compatible. I suppose we could walk up the
fwnode tree until we do find a node with a compatible property,
that may work.

-- 
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