PmwOut: Add method to enable/disable PWM

The new method can be called to disable PWM to not block deep sleep

Author: hugueskamba

drivers/PwmOut.h

@@ -118,6 +118,17 @@ class PwmOut {
      */
     void pulsewidth_us(int us);
 
+    /** Enable or disable PWM
+     *
+     * Control enabling of device's PWM. This is primarily intended
+     * for temporary power-saving; This call can
+     * allow pwm to be temporarily disabled to permit power saving without
+     * losing device state.
+     *
+     * @param enabled       true to enable, false to disable.
+     */
+    void enable_pwm(bool enabled = true);
+
     /** A operator shorthand for write()
      *  \sa PwmOut::write()
      */

drivers/source/PwmOut.cpp

@@ -98,6 +98,19 @@ void PwmOut::pulsewidth_us(int us)
     core_util_critical_section_exit();
 }
 
+void PwmOut::enable_pwm(bool enabled)
+{
+    core_util_critical_section_enter();
+    if (_deep_sleep_locked == enabled) {
+        if (enabled) {
+            PwmOut::unlock_deep_sleep();
+        } else {
+            PwmOut::lock_deep_sleep();
+        }
+    }
+    core_util_critical_section_exit();
+}
+
 void PwmOut::lock_deep_sleep()
 {
     if (_deep_sleep_locked == false) {