Initial PWM support for the CHIP even though the base .dtb does not support, this is untested

source/c_pwm.h

@@ -0,0 +1,36 @@
+/*
+Copyright (c) 2016 Robert Wolterman
+
+Original BBIO Author Justin Cooper
+Modified for CHIP_IO Author Robert Wolterman
+
+This file incorporates work covered by the following copyright and
+permission notice, all modified code adopts the original license:
+
+Copyright (c) 2013 Adafruit
+Author: Justin Cooper
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+int pwm_start(const char *key, float duty, float freq, int polarity);
+int pwm_disable(const char *key);
+int pwm_set_frequency(const char *key, float freq);
+int pwm_set_duty_cycle(const char *key, float duty);
+void pwm_cleanup(void);