what is the difference between Linux drivers and Android driver

As android kernel is a hacked version of linux kernel..

So the way we write drivers for linux would that work in android or some modifications are to be done .?

Answer

There are some API differences between Android and Linux kernel drivers code, any drivers written for Android hardware platforms can not get merged into the main kernel tree because they have dependencies on code that only lives in Google’s kernel tree, causing it to fail to build in the kernel.org tree.

“Android and Linux are growing back together” would give you more insight to your question.