make HAL component driver file

Hello i am new to linuxcnc.
right now i am working making drivers of BSPI for 5i24 but cannot understand its function.
can anyone plz suggest good reference to start...

Thanks
Kaushik

Probably the best place to look is the 7I65 hal component since
its a working hal component that interfaces to BSPI:

mesa_7i65.comp

Thanks but I checked that comp file but I am not getting from where he is getting dat value in hm2_bspi_write_chan ie 0x0000A000, 0x00008000 and 0x00009c18 and also cpld values

All SPI data is specific to the actual remote SPI devices so
those numbers only make sense for the specific hardware on the 7I65

Okay..
Thanks