pwm: Added API for PWM.

* Added include line on main maa header to include PWM definitions.

Signed-off-by: Thomas Ingleby <thomas.c.ingleby@intel.com>

api/maa.h

@@ -27,6 +27,7 @@
 #include "i2c.h"
 #include "i2cslave.h"
 #include "gpio.h"
+#include "pwm.h"
 
 #define MAA_LIBRARY_VERSION 1
 

api/pwm.h

@@ -0,0 +1,128 @@
+/*
+ * Author: Thomas Ingleby <thomas.c.ingleby@intel.com>
+ *
+ * Copyright © 2014 Intel Corporation
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <stdio.h>
+#include <fcntl.h>
+
+namespace maa {
+
+/** A PWM object, used for interacting with PWM output.
+ *
+ * Example:
+ * @code
+ * // Set up PWM object then cycle percentage 0-100.
+ *
+ * #include "maa.h"
+ *
+ * PWM pwm(3);
+ *
+ * int main() {
+ *     pwm.period_us(7968750i); //Max Galileo Rev D
+ *     pwm.enable(1);
+ *
+ *     float value = 0;
+ *     while(1) {
+ *         pwm.write(value);
+ *         sleep(0.5);
+ *         if(value == 1.0) {
+ *             value = 0;
+ *         } else {
+ *             value = value +0.1;
+ *         }
+ *     }
+ * }
+ * @endcode
+ */
+class PWM {
+
+public:
+
+    /** Create an PWM object
+     *
+     *  @param pin The PWM pin to operate on.
+     */
+    PWM(int pin);
+
+    /** Set the ouput duty-cycle percentage, as a float
+     *
+     *  @param percentage A floating-point value representing percentage of output.
+     *    The value should lie between 0.0f (representing on 0%) and 1.0f
+     *    Values above or below this range will be set at either 0.0f or 1.0f.
+     */
+    void write(float percentage);
+
+    /** Read the ouput duty-cycle percentage, as a float
+     *
+     *  @return percentage A floating-point value representing percentage of output.
+     *    The value should lie between 0.0f (representing on 0%) and 1.0f
+     *    Values above or below this range will be set at either 0.0f or 1.0f.
+     */
+    float read();
+
+    /** Set the PWM period as seconds represented in a float
+     *
+     *  @param seconds Peroid represented as a float in seconds.
+     */
+    void period(float seconds);
+
+    /** Set period. Microseconds.
+     *  @param ms microseconds for period.
+     */
+    void period_ms(int ms);
+
+    /** Set period. Nanoseconds
+     *  @param ns nanoseconds as period.
+     */
+    void perod_us(int us);
+
+    /** Set pulsewidth, As represnted by seconds in a (float).
+     *  @param seconds The duration of a pulse
+     */
+    void pulsewidth(float seconds);
+
+     /** Set pulsewidth. Microseconds
+     *  @param ms microseconds for pulsewidth.
+     */
+    void pulsewidth_ms(int ms);
+
+      /** Set pulsewidth, nanoseconds.
+     *  @param us nanoseconds for pulsewidth.
+     */
+    void pulsewidth_us(int us);
+
+    /** Set the enable status of the PWM pin. None zero will assume on with output being driven.
+     *   and 0 will disable the output.
+     *  @param enable enable status of pin
+     */
+    void enable(int enable);
+
+     /** Close and unexport the PWM pin.
+     */
+    void close();
+
+};
+}