Thank you very much.
I guess one of your links is where I found the code. Anyway - I now see that there are 3 "generic" drivers: 5780, 57xx and 5791. They are all written by Dan.Nechita@analog.com, so it should be a piece of cake to study (18/20 bit, general "feel and style") and modify/incorporate elsewhere.
Also - the commands https://github.com/analogdevicesinc/no-OS/tree/master/device_commands/AD5791 seems to be generic.
However - ADI uses visa/labview for the GUI. I won't touch anything from NI. Do you have any C code for configuring, data transmission and result display / graphing on PC? By anything I mean anything (SPI and DAC commands are now taken care of - all that is left is a C code skeleton for the PC like for instance the Microchip Data View (free code - "scope plot" and histogram)).
Thanks again.
Roy