overload InterruptIn constructor to allow PinMode control

drivers/InterruptIn.cpp

@@ -24,11 +24,20 @@ InterruptIn::InterruptIn(PinName pin) : gpio(),
                                         _rise(NULL),
                                         _fall(NULL) {
     // No lock needed in the constructor
-
     gpio_irq_init(&gpio_irq, pin, (&InterruptIn::_irq_handler), (uint32_t)this);
     gpio_init_in(&gpio, pin);
 }
 
+InterruptIn::InterruptIn(PinName pin, PinMode mode) :
+                                        gpio(),
+                                        gpio_irq(),
+                                        _rise(NULL),
+                                        _fall(NULL) {
+    // No lock needed in the constructor
+    gpio_irq_init(&gpio_irq, pin, (&InterruptIn::_irq_handler), (uint32_t)this);
+    gpio_init_in_ex(&gpio, pin, mode);
+}
+
 InterruptIn::~InterruptIn() {
     // No lock needed in the destructor
     gpio_irq_free(&gpio_irq);

drivers/InterruptIn.h

@@ -66,6 +66,12 @@ public:
      *  @param pin InterruptIn pin to connect to
      */
     InterruptIn(PinName pin);
+    /** Create an InterruptIn connected to the specified pin,
+     *  and the pin configured to the specified mode.
+     *
+     *  @param pin InterruptIn pin to connect to
+     */
+    InterruptIn(PinName pin, PinMode mode);
     virtual ~InterruptIn();
 
     /** Read the input, represented as 0 or 1 (int)