> > In general, we try to have the PHY add the delay, not the MAC. So i > > would start with hard coding the delay to 0ns, and only implement > > these properties if you have a board where the PHY cannot add the > > delay. > > If I understand the KSZ9031 bindings correctly, that PHY is limited to > a skew of up to 960 ps, not 1800 or 2000 ps. Reading ksz9031_config_rgmii_delay(), it implements the four PHY_INTERFACE_MODE_RGMII* interface modes. So it should be able to provide the 2ns delay. Sometimes the tuning ability is relative to the base delay. So maybe it can do 2n +- 0.960/2 ? Anyway, try interface mode "rgmii_id" with the MAC not providing any delay. Andrew
