i've tried ps3 controller connected on OTG, and readed something about playing around on a SNES emu and ifso done just disconnect youre controller. and turn on bluetooth and you will see that youre controller is already paired with youre phone( weird as it is but its PAIRED!! )
and so yeah i've played some old school mario on my phone on the emu. and ive turned on the bluetooth and it definitly works. but the thing is there's no keymapping app for the ps3 controller around.
so im on sixaxis controller app which is worth 5 stars in my oppinion, just search for it on store and you will be able to almost connect each bluetooth controller and remapp all the buttons.