DSA: request for your help with your DSA driver

[Alvin Šipraga]

Hi Marek,

On Tue, Jul 05, 2022 at 02:22:36PM +0200, Marek Behún wrote:
> Hello guys,
> 
> this is a request for help/comments on the DSA drivers you have been
> working on in Linux.
> 
> I am writing this e-mail because people don't seem to be responding to
> RFC patches.
> 
> Basically Russell and I are trying to do some development on phylink +
> DSA to move it forward, without breaking existing drivers:
> 
> - we want to make it so that phylink is always used for CPU and DSA
>   ports (needed for conversion to phylink_pcs)
> 
> - to do that, phylink needs to know the interface type to which the
>   port will be configure

<snip>

> 
> It is very probable that this will break your drivers, and so I ask you
> to look at the RFC series, maybe test it, and give your comments or
> additional patches that make it work.

For drivers/net/dsa/realtek/rtl8365mb:

I think we are OK. The .phylink_get_caps op will populate
supported_interfaces faithfully for all port types, so in the absence of
a fixed-link I think it is perfectly fine for phylink to calculate the
highest speed interface and use that. The driver and hardware will be
able to support whatever it advertises.

From reading the series I understand that the behaviour for DTs with
fixed-link will remain unchanged.

With the above in mind, I think it's fine not to set default_interface
in the .phylink_get_caps callback? This means "let phylink decide the
most suitable default".

Kind regards,
Alvin