Subsurface is awesome and it runs on Windows, Linux and Mac. And supports MANY different dive computers.
My Subsurface log has dives downloaded from an Oceanic Atom, a Hollis TX-1, a Seabear H3, a Petrel 2 and someday it will have dives downloaded from my Perdix AI.
When I download the same dive from 2 different computers, Subsurface even automatically merges them together so it only shows as one dive in my log, but I can view the dive and toggle between which computer's data it is actually showing.
And Subsurface also has a built-in dive planner module, too, so you can enter dive parameters for a dive you are thinking about and it will show you if you are planning for a bottom time that is too long and will require deco stops, plus it will tell you how much gas is required to do the planned dive.
And, as has already been said, it is FREE. You can even download the source code and build or modify it yourself, if so inclined.