RC_Channel: added channel_function()

this is used in the plane mixing code

ArduPlane/ArduPlane.pde

@@ -350,10 +350,8 @@ static uint8_t oldSwitchPosition = 254;
 // This is used to enable the inverted flight feature
 static bool inverted_flight     = false;
 
-#if CONFIG_HAL_BOARD == HAL_BOARD_PX4
 // This is used to enable the PX4IO override for testing
-static bool px4io_override_enabled     = false;
-#endif
+static bool px4io_override_enabled = false;
 
 static struct {
     // These are trim values used for elevon control

libraries/RC_Channel/RC_Channel_aux.cpp

@@ -65,6 +65,19 @@ void RC_Channel_aux::disable_aux_channel(uint8_t channel)
     }    
 }
 
+/*
+  return the current function for a channel
+*/
+RC_Channel_aux::Aux_servo_function_t RC_Channel_aux::channel_function(uint8_t channel)
+{
+    for (uint8_t i = 0; i < RC_AUX_MAX_CHANNELS; i++) {
+        if (_aux_channels[i] && _aux_channels[i]->_ch_out == channel) {
+            return (RC_Channel_aux::Aux_servo_function_t)_aux_channels[i]->function.get();
+        }
+    }    
+    return RC_Channel_aux::k_none;
+}
+
 /// Update the _aux_channels array of pointers to rc_x channels
 /// This is to be done before rc_init so that the channels get correctly initialized.
 /// It also should be called periodically because the user might change the configuration and

libraries/RC_Channel/RC_Channel_aux.h

@@ -121,6 +121,9 @@ public:
     // prevent a channel from being used for auxillary functions
     static void disable_aux_channel(uint8_t channel);
 
+    // return the current function for a channel
+    static Aux_servo_function_t channel_function(uint8_t channel);
+
 private:
     static uint32_t _function_mask;
     static RC_Channel_aux *_aux_channels[RC_AUX_MAX_CHANNELS];