one analogue stick 8 octaves, for 8 directions
4 top bottons and up on the digital pad, 5 black notes
7 white notes 4 face buttons, 3 left, down right on digital

just an idea, the other analogue stick and stick button could be used to move the cursor on the piano roll, or to use a menu play and rewind the song, that comes up when the stick is moved,
using this joystick button to select
, like the mouse click is used.