Norwegian naming patterns

Hello again I really hope I have posted this in the correct forum, I seem to have a habit of being in the wrong place, so please forgive me if I am . I have asked about a certain ancestor a few years ago, and had a lot of info, which really helped. As I am now going to pick back up where I had left off, I wondered if I could ask about the norwegian surname johanneson. My ggrandfather from Wales Samuel Johnson (was johansen/johannesson etc, etc. I have just found somebody else with a family tree, which includes the same samuel. It names his father as John Margison Johnson. wondered if this could throw any light on the ancestors before. Any possible names spring to anyones m, ind ? (I COULD BE TOTALLY WRONG) but could his fathers sur name be margisson?????sorry if I sound stupid.