In UG1085, Zynq UltraScale+ Device TRM, page 1044, the IOP_SWITCH_CLK is referenced as the clock source for the MDC signal. In Vivado (v2018.1), an IOU_SWITCH clock is setup in "Clock Configuration" but there is no IOP_SWITCH_CLK. Also, in UG1085, the IOU_SWITCH clock is also referenced in two places. I suspect these are referring to the same clock. Please confirm these are the same clock or let me know how to setup the IOP_SWITCH clock.