As far as I understand there is no legal way to use input devices like keyboard and mouse in GF application without 
photon.

I've found gfi_* interface in GF headers, but it is not documented. Also exist libhiddi and its headers, which looks a 
bit better than gfi_* interface, but there is no documentation also.

Interface declared in sys/hiddi.h is very obscured to find out what I must do to handle keyboards and mice.

Utility hidview does exactly what I need when -a or -A command line option is specified. Maybe it is possible to open 
hidview source files if there is no hiddi documentation available ?