Hello Mohanasundaram,
Therefore, based on your last response, you are within the SPI dynamic parameters. The SC16IS762 device supports SPI clock speeds up to 15 Mbit/s.
In this case, could you please share a detailed description of your issue? Are you able to interface with the device?
You may find a SC16IS750_Linux driver attached. I do recommend to use it as a reference for your design.
Regards,
David