Questions about repo and git submodule

All,

I have some questions about android repo and git submodule.

I created a repo repository with below commands:
1.  repo init -u git://android.git.kernel.org/platform/manifest.git
2.  repo initialized in /android

1. The android dir is not a git repository, if other people clone my
android code, how does it work?
2. I want to make android dir to be a git repository, is it workable
that I create submodule for each subdirectory in another directory? Is
there a script for it?

Thank you ！

Emily