From a7fe242e317d43f217e9d84180784ed1d54de8d8 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Fri, 23 Feb 2018 16:33:49 +1100
Subject: [PATCH] Copter: add option to disable RTL flight mode

---
 ArduCopter/APM_Config.h | 1 +
 ArduCopter/Copter.h     | 2 ++
 ArduCopter/config.h     | 6 ++++++
 ArduCopter/events.cpp   | 2 ++
 ArduCopter/mode.cpp     | 2 ++
 5 files changed, 13 insertions(+)

diff --git a/ArduCopter/APM_Config.h b/ArduCopter/APM_Config.h
index c254703f52..ad546791f7 100644
--- a/ArduCopter/APM_Config.h
+++ b/ArduCopter/APM_Config.h
@@ -28,6 +28,7 @@
 //#define MODE_GUIDED_ENABLED   DISABLED            // disable guided mode support
 //#define MODE_LOITER_ENABLED   DISABLED            // disable loiter mode support
 //#define MODE_POSHOLD_ENABLED  DISABLED            // disable poshold mode support
+//#define MODE_RTL_ENABLED DISABLED                 // disable rtl mode support
 //#define MODE_SMARTRTL_ENABLED DISABLED            // disable smartrtl mode support
 //#define MODE_SPORT_ENABLED DISABLED               // disable sport mode support
 
diff --git a/ArduCopter/Copter.h b/ArduCopter/Copter.h
index 97d7d711e8..a173df9f02 100644
--- a/ArduCopter/Copter.h
+++ b/ArduCopter/Copter.h
@@ -978,7 +978,9 @@ private:
 #if MODE_POSHOLD_ENABLED == ENABLED
     ModePosHold mode_poshold;
 #endif
+#if MODE_RTL_ENABLED == ENABLED
     ModeRTL mode_rtl;
+#endif
 #if FRAME_CONFIG == HELI_FRAME
     ModeStabilize_Heli mode_stabilize;
 #else
diff --git a/ArduCopter/config.h b/ArduCopter/config.h
index e040b56f67..0fcdc63517 100644
--- a/ArduCopter/config.h
+++ b/ArduCopter/config.h
@@ -297,6 +297,12 @@
 # define MODE_POSHOLD_ENABLED ENABLED
 #endif
 
+//////////////////////////////////////////////////////////////////////////////
+// RTL - Return To Launch
+#ifndef MODE_RTL_ENABLED
+# define MODE_RTL_ENABLED ENABLED
+#endif
+
 //////////////////////////////////////////////////////////////////////////////
 // SmartRTL - allows vehicle to retrace a (loop-eliminated) breadcrumb home
 #ifndef MODE_SMARTRTL_ENABLED
diff --git a/ArduCopter/events.cpp b/ArduCopter/events.cpp
index aaadb2811d..39dac52b12 100644
--- a/ArduCopter/events.cpp
+++ b/ArduCopter/events.cpp
@@ -189,8 +189,10 @@ void Copter::failsafe_terrain_on_event()
 
     if (should_disarm_on_failsafe()) {
         init_disarm_motors();
+#if MODE_RTL_ENABLED == ENABLED
     } else if (control_mode == RTL) {
         mode_rtl.restart_without_terrain();
+#endif
     } else {
         set_mode_RTL_or_land_with_pause(MODE_REASON_TERRAIN_FAILSAFE);
     }
diff --git a/ArduCopter/mode.cpp b/ArduCopter/mode.cpp
index d75b91f823..84b9c3a0df 100644
--- a/ArduCopter/mode.cpp
+++ b/ArduCopter/mode.cpp
@@ -76,9 +76,11 @@ Copter::Mode *Copter::mode_from_mode_num(const uint8_t mode)
             ret = &mode_land;
             break;
 
+#if MODE_RTL_ENABLED == ENABLED
         case RTL:
             ret = &mode_rtl;
             break;
+#endif
 
 #if MODE_DRIFT_ENABLED == ENABLED
         case DRIFT: