RIOT-OS/RIOT — pull request #1466 by haukepetersen (2014-07-24 14:10:19+00:00)
Title: drivers: improvements to the low-level pwm driver interface

Adjusted the pwm driver interface slightly, most notably removed the anti-pattern of having an `UNDEFINED` value in the device enum in favor of a guard around the complete header/implementation files.

This PR is the first step in improving all existing low-level driver interfaces...