UG-570 page 113 says SPI_CLK maximum frequency is 50 MHz. The FMCOMMS5 eval card is running the SPI at 166.66MHz. Can you please comment on this discrepancy between the data sheet and the eval hardware?
UG-570 is correct.
Can you please share reference where you are seeing SPI for FMCOMMS5 as 166.66MHz.
166.66 MHz is the clock for the SPI controller in the Zynq. I.e. the clock that is clocking the logic inside the Zynq. This is not the frequency of the external SPI clock. The SPI clock is a down divided version of that clock and the reference design makes sure that it doesn't run the SPI clock faster than what is supported by the hardware.
spi-max-frequency = <10000000>;
This means that the SPI does not run faster as 10MHz.
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