The Ethernet from Freescale states;
* The dual fec interfaces are not equivalent with enet-mac.
* Here are the differences:
* - fec0 supports MII & RMII modes while fec1 only supports RMII
* - fec0 acts as the 1588 time master while fec1 is slave
* - external phys can only be configured by fec0
* That is to say fec1 can not work independently. It only works
* when fec0 is working. The reason behind this design is that the
* second interface is added primarily for Switch mode.
* Because of the last point above, both phys are attached on fec
* mdio interface in board design, and need to be configured by
* fec0 mii_bus.
Does this means that 1588 timing synchronization can only be achieved from the ENET1 input?