[PATCH net-next v3 1/7] net: dsa: mt7530: empty default case on mt7530_setup_port5()

[Vladimir Oltean]

On Fri, Feb 02, 2024 at 06:05:36PM +0000, Russell King (Oracle) wrote:
> > > Given everything I've said above, the only way to configure RGMII
> > > delays is via the rx-internal-delay-ps and tx-internal-delay-ps
> > > properties. So, DSA drivers should _not_ be configuring their ports
> > > with RGMII delays based on the RGMII phy interface mode.
> > > 
> > > The above is my purely logically reasoned point of view on this
> > > subject. Others may have other (to me completely illogical)
> > > interpretations that can only lead to interoperability issues.
> > 
> > I will address this with the next patch series. Thank you for explaining it
> > in detail.
> 
> This is a good time to point out not to rush with the next patch
> series, as my email will _likely_ provoke some additional discussion
> from Andrew and/or Vladimir. So please give it a few days (maybe
> around the middle of next week) to give them time to consider my
> email and respond.

I agree with everything you've said. The only problem is that
Documentation/devicetree/bindings/net/ethernet-controller.yaml is
ambiguous on this topic (to put it mildly).

@Arınç, there are ways to handle the "tx-internal-delay-ps" in
mt7530_setup_port5() in a way that is backwards compatible. I don't know
about RX delays - the function doesn't handle them, and I don't have the
time to open datasheets now. You can take inspiration from
ksz_parse_rgmii_delay() and sja1105_parse_rgmii_delays() on how to only
fall back to the current logic to set the tx_delay if the more specific
OF properties are not present.