The mpsutil (and mprutil) tool states these commands in its usage message:

Commands include:
debug dumpreqs                                  Dump the active request queue
flash save [firmware|bios] [file]               Save firmware/bios into a file
flash update [firmware|bios] file               Update firmware/bios
show adapter                                    display controller information
show iocfacts                                   Show IOC Facts Message
show adapters                                   Show a summary of all adapters
show all                                Show all devices
show devices                                    Show attached devices
show enclosures                                 Show attached enclosures
show expanders                                  Show attached expanders
show cfgpage page [num] [addr]                  Display config page
slot set status <enclosure handle> <slot number> <status>       Set status of the slot in the directly attached enclosure
version                                 version


While all show/flash subcommands are described in the manpage, the 'debug dumpregs' and 'slot set status' commands aren't.
'debug dumpregs' doesn't take arguments and is quite self-explanatory, but the 'slot set status' command needs arguments of which only the enclosure handle and slot number could be extracted e.g. from an 'mpsutil show devices' listing. However, the 'status' (which needs to be a numerical argument) can't be guessed from any output of mpsutil/mprutil and isn't mentioned in any of the mpr/mprutil/mps/mpusutil manpages.