AP_LandingGear: add startup position selection parameter

libraries/AP_LandingGear/AP_LandingGear.cpp

@@ -26,9 +26,33 @@ const AP_Param::GroupInfo AP_LandingGear::var_info[] = {
     // @User: Standard
     AP_GROUPINFO("SERVO_DEPLOY", 1, AP_LandingGear, _servo_deploy_pwm, AP_LANDINGGEAR_SERVO_DEPLOY_PWM_DEFAULT),
 
+    // @Param: STARTUP
+    // @DisplayName: Landing Gear Startup position
+    // @Description: Landing Gear Startup behaviour control
+    // @Values: 0:WaitForPilotInput, 1:Retract, 2:Deploy
+    // @User: Standard
+    AP_GROUPINFO("STARTUP", 2, AP_LandingGear, _startup_behaviour, (uint8_t)AP_LandingGear::LandingGear_Startup_WaitForPilotInput),
+
     AP_GROUPEND
 };
 
+/// initialise state of landing gear
+void AP_LandingGear::init()
+{
+    switch ((enum LandingGearStartupBehaviour)_startup_behaviour.get()) {
+        default:
+        case LandingGear_Startup_WaitForPilotInput:
+            // do nothing
+            break;
+        case LandingGear_Startup_Retract:
+            retract();
+            break;
+        case LandingGear_Startup_Deploy:
+            deploy();
+            break;
+    }
+}
+
 /// set landing gear position to retract, deploy or deploy-and-keep-deployed
 void AP_LandingGear::set_position(LandingGearCommand cmd)
 {

libraries/AP_LandingGear/AP_LandingGear.h

@@ -21,6 +21,13 @@ public:
         LandingGear_Deploy_And_Keep_Deployed,
     };
 
+    // Gear command modes
+    enum LandingGearStartupBehaviour {
+        LandingGear_Startup_WaitForPilotInput = 0,
+        LandingGear_Startup_Retract = 1,
+        LandingGear_Startup_Deploy = 2,
+    };
+
     /// Constructor
     AP_LandingGear()
     {
@@ -28,6 +35,9 @@ public:
         AP_Param::setup_object_defaults(this, var_info);
     }
 
+    /// initialise state of landing gear
+    void init();
+
     /// returns true if the landing gear is deployed
     bool deployed() const { return _deployed; }
 
@@ -41,6 +51,7 @@ private:
     // Parameters
     AP_Int16    _servo_retract_pwm;     // PWM value to move servo to when gear is retracted
     AP_Int16    _servo_deploy_pwm;      // PWM value to move servo to when gear is deployed
+    AP_Int8     _startup_behaviour;     // start-up behaviour (see LandingGearStartupBehaviour)
 
     // internal variables
     bool        _deployed;              // true if the landing gear has been deployed, initialized false