Re: [PATCH 1/3] dt-bindings: dsa: microchip: add KSZ low-loss cable errata properties

[Andrew Lunn]

> Regarding the difference between the two workarounds:
> Microchip’s errata does provide some insight into how they behave and when
> each should be used.
> Workaround 1 modifies the PHY equalizer settings by adjusting an indirect
> register (0x3c).
> According to Microchip’s support article:

....


Thanks for the documentation. This needs to go somewhere.

Not sure where yet. If we stay with a DT setting, it should be in the
DT binding. If we make it a PHY tuneable, maybe a comment in the PHY
driver, and in the commit message?

> Regarding the question of whether this should be exposed through a PHY
> tunable:
> I understand your concern. The erratum is indeed linked to cable
> characteristics, not the board itself.
> Since this patch modifies registers that belong to the DSA switch itself,
> and not the PHY driver,

I need to go look at the code, but maybe we can make use of the fact
the PHY is embedded within the switch, rather than being a discrete
device. So we can safely break the layering, even if it is
architecturally wrong.

	Andrew