Fix PwmOut::resume() for static pinmap usage (#281)

* Fix PwmOut::resume() for static pinmap usage

* Use function pointers, like SPI does

* Fix style

* Remove "static"

* Revert "Remove "static""

This reverts commit c009297.

drivers/include/drivers/PwmOut.h

@@ -63,7 +63,8 @@ class PwmOut {
 
     /** Create a PwmOut connected to the specified pin
      *
-     *  @param pinmap reference to structure which holds static pinmap.
+     * @param pinmap reference to structure which holds static pinmap.
+     *   This reference is stored in the PwmOut, so the pinmap needs to live as long as this object does.
      */
     PwmOut(const PinMap &pinmap);
     PwmOut(const PinMap &&) = delete; // prevent passing of temporary objects
@@ -199,14 +200,28 @@ class PwmOut {
     /** Unlock deep sleep in case it is locked */
     void unlock_deep_sleep();
 
+    // Functions which call the underlying HAL init function.  The direct one calls the static
+    // pinmap version (pwmout_init_direct()) and the normal one calls the PinName-accepting one (pwmout_init()).
+    // A pointer to one of these two functions is stored in the _init_func member.
+    // It's done this way so that references to pwmout_init(), and therefore to the pinmap tables,
+    // can be removed by the linker if only the static pinmap version is used.
+    static void _call_pwmout_init_direct(PwmOut *thisPtr);
+    static void _call_pwmout_init(PwmOut *thisPtr);
+
     /** Initialize this instance */
     void init();
 
     /** Power down this instance */
     void deinit();
 
     pwmout_t _pwm;
-    PinName _pin;
+
+    const PinName _pin; // Pin, NC if using static pinmap
+    PinMap const *const _pinmap;  // Static pinmap, nullptr if not used
+
+    /* Pointer to HAL init function */
+    void (*_init_func)(PwmOut *);
+
     bool _deep_sleep_locked;
     bool _initialized;
     float _duty_cycle;

drivers/source/PwmOut.cpp

@@ -28,6 +28,8 @@ namespace mbed {
 
 PwmOut::PwmOut(PinName pin) :
     _pin(pin),
+    _pinmap(nullptr),
+    _init_func(_call_pwmout_init),
     _deep_sleep_locked(false),
     _initialized(false),
     _duty_cycle(0),
@@ -36,11 +38,16 @@ PwmOut::PwmOut(PinName pin) :
     PwmOut::init();
 }
 
-PwmOut::PwmOut(const PinMap &pinmap) : _deep_sleep_locked(false)
+PwmOut::PwmOut(const PinMap &pinmap) :
+    _pin(NC),
+    _pinmap(&pinmap),
+    _init_func(_call_pwmout_init_direct),
+    _deep_sleep_locked(false),
+    _initialized(false),
+    _duty_cycle(0),
+    _period_us(0)
 {
-    core_util_critical_section_enter();
-    pwmout_init_direct(&_pwm, &pinmap);
-    core_util_critical_section_exit();
+    PwmOut::init();
 }
 
 PwmOut::~PwmOut()
@@ -164,12 +171,25 @@ void PwmOut::unlock_deep_sleep()
     }
 }
 
+void PwmOut::_call_pwmout_init_direct(PwmOut *thisPtr)
+{
+    pwmout_init_direct(&thisPtr->_pwm, thisPtr->_pinmap);
+}
+
+void PwmOut::_call_pwmout_init(PwmOut *thisPtr)
+{
+    pwmout_init(&thisPtr->_pwm, thisPtr->_pin);
+}
+
 void PwmOut::init()
 {
     core_util_critical_section_enter();
 
     if (!_initialized) {
-        pwmout_init(&_pwm, _pin);
+
+        // Call either pwmout_init() or pwmout_init_direct(), depending on whether we have a PinName or a static pinmap
+        _init_func(this);
+
         lock_deep_sleep();
         _initialized = true;
     }