I want to use PS programming to program Cyclone 10LP FPGA directly from a microprocessor. Can I convert the sof file to rbf file using Quartus and just send it in SPI to the FPGA or I need to use some special driver?

Hi,

Yes, You can use the external host such as a MAX® V device, microprocessor with flash memory, or a download cable to control the transfer of configuration data from an external storage such as flash memory to the FPGA. The design that controls the configuration process resides in the external host.Also you can use SPI to transfer data to fpga.

Refer section 6.1.2. from below link.

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/cyclone-10/c10lp-51003.pdf

Let me know if this has helped resolve the issue you are facing or if you need any further assistance.

Regards

Anand