> Since clause 45 PHYs are identified by the "ethernet-phy-ieee802.3-c45"
> compatible string (otherwise they are C22), then a PHY which is not
> described in the device tree can only be C22. So this is why
> ds->slave_mii_bus only deals with clause 22 methods, and the true reason
> behind the comment above.
>
> But actually this premise is no longer true since Luiz' commit
> fe7324b93222 ("net: dsa: OF-ware slave_mii_bus"), which introduced the
> strange concept of an "OF-aware helper for internal PHYs which are not
> described in the device tree". After his patch, it is possible to have
> something like this:
>
> ethernet-switch {
> ethernet-ports {
> port@1 {
> reg = <1>;
> };
> };
>
> mdio {
> ethernet-phy@1 {
> compatible = "ethernet-phy-ieee802.3-c45"
> reg = <1>;
> };
> };
> };
>
> As you can see, this is a clause 45 internal PHY which lacks a
> phy-handle, so its bus must be put in ds->slave_mii_bus in order for
> dsa_slave_phy_connect() to see it without that phy-handle (based on the
> port number matching with the PHY number). After Luiz' patch, this kind
> of device tree is possible, and it invalidates the assumption about
> ds->slave_mii_bus only driving C22 PHYs.
My memory is hazy, but i think at the time i wrote these patches,
there was no DSA driver which made use of ds->slave_mii_bus with
C45. So i took the short cut of only supporting C22.
Those DSA drivers which do support C45 all register their bus directly
with the MDIO core.
So Luiz patches may allow a C45 bus, but are there any drivers today
actually using it?
Andrew
