void hwi_add_rtc(const char *name, paddr_t base, unsigned reg_shift, unsigned len, int mmap, int cent_reg);
Add an hwi_device item describing the realtime clock to the hwinfo section. The name of the device is name. The hwi_location tag items are given by base, reg_shift, len, and mmap. The mmap parameter indicates if the device is memory-mapped or I/O-space-mapped and is used to set the addrspace field.
If the cent_reg parameter is not -1, it's used to add an hwi_regname tag with the offset field set to its value. This indicates the offset from the start of the device where the century byte is stored.