This patchset introduces a new custom directive called 'drivers-doc' which loads all available drivers under a given namespace and import their respective docstring into the .rst document. This patchset also contains some modification/addition to the docstring of these drivers to make the final document complete. Change-Id: Ib3df59fa45cea9d11d20fb73a5f0f1d564135bca Closes-Bug: #1536218 Closes-Bug: #1536735