gpio: added pinmap accessor for introspection usage

gpio.go

@@ -125,6 +125,9 @@ type PWMPin interface {
 
 // GPIODriver implements a generic GPIO driver.
 type GPIODriver interface {
+	// Returns the pinmap for this GPIODriver
+	PinMap() PinMap
+
 	// Unregister unregisters the pin from the driver. Should be called when the pin is closed.
 	Unregister(string) error
 

gpiodriver.go

@@ -107,6 +107,10 @@ func (io *gpioDriver) PWMPin(key interface{}) (PWMPin, error) {
 	return p, nil
 }
 
+func (io *gpioDriver) PinMap() PinMap {
+	return io.pinMap
+}
+
 func (io *gpioDriver) Close() error {
 	for _, p := range io.initializedPins {
 		if err := p.Close(); err != nil {