You can refer to the below stated example applications for more details on how to use clockps driver.

xclockps_i2c_example.c

Contains an example on how to use the XClockPs driver directly. This example uses xclockps APIs to enable the I2C0_REF clock. It then uses set and get APIs to set and get the I2C0_REF clock rates.

For details, see xclockps_i2c_example.c.