I want to reverse the coordinate origin in Inkscape to top left corner. By default (0,0) stays at bottom left. Changing it to top left corner will help me in designing a sprite sheet for my game.
You can't. There's an ongoing change to address this an additional work on making it user-configurably. https://bugs.launchpad.net/inkscape/+bug/170049
It's targetted to the 0.49 release so perhaps if you try a "nightly" it'll have what you're after?