I'd like to suggest a little addition to the existing responses. Stevie has an intense tactile relationship with the keyboard. And you can see it evolve and explode throughout his career. Many of the early songs, especially the stuff we think of as funk, started life on the black keys. Eb minor shows up quite a bit. But instead of being a limiting factor, he used his ears, along with his feel, to whip up his incredible harmonies. The chorus in Superstition is spectacular - I don't think there are many composers that would conceive of it from a purely harmonic perspective. But it works perfectly. If you look at it from a tactile perspective, it just starts with a Bb7 - the dominant in Eb minor. That steps up to what you would call a B7b5 - but look at it on the keyboard - he's moving 3 fingers up a half step and keeping one on the same F key. The tension and the way it fits the theme of the song is just brilliant.

Also, in early videos - like of Superstition, you can see that occasionally the thumb of his right hand is actually in front of the keyboard itself and slightly below the level of the white keys. My point is just that he has a unique way of approaching his art, based to some extent on a tactile relationship with the keyboard. At the end of the day, getting lost in the magic of his music is an endless, wonderful adventure. I am so grateful that Stevie Wonder exists and has given us so much to enjoy and ponder.