I probably raise here if I think the guy is good enough to try to raise to knock out the button and see the river for free (spade draw). If you haven't seen him raise with a draw like that I would probably slow down if he's real straightforward and only bets TP.

If he's that passive you could be up against a set of Q's, 9's or 5's or maybe AQ and he's trying to face the button with 2 cold in case he has spades??

Unless I've seen him raise a draw (which most unimaginative folks at these limits don't do) I probably call and check/fold the turn.