The CPTS module should be configured as:
- Reset the CPTS module.
- Clear the CPTS_EN bit in the CPTS_CONTROL register.
- Write the CLKSEL_RFT value in the CM_GMAC_GMAC_CLKCTRL register in the PRCM with the desired reference clock selection.
- Set the CPTS_EN bit in the CPTS_CONTROL register.
- If using interrupts and not polling, enable the interrupt by setting the TS_PEND_EN bit in the CPTS_INT_ENABLE register.