From fec2025469dc75dd090935fd600d1ccd54e62a65 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Fri, 13 Mar 2015 22:32:35 +1100
Subject: [PATCH] AP_Compass: added set_hil_mode()

---
 libraries/AP_Compass/Compass.cpp | 7 ++++++-
 libraries/AP_Compass/Compass.h   | 6 ++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_Compass/Compass.cpp b/libraries/AP_Compass/Compass.cpp
index 4e4ed0b39f..2dbe052a62 100644
--- a/libraries/AP_Compass/Compass.cpp
+++ b/libraries/AP_Compass/Compass.cpp
@@ -280,7 +280,8 @@ Compass::Compass(void) :
     _thr_or_curr(0.0f),
     _backend_count(0),
     _compass_count(0),
-    _board_orientation(ROTATION_NONE)
+    _board_orientation(ROTATION_NONE),
+    _hil_mode(false)
 {
     AP_Param::setup_object_defaults(this, var_info);
     for (uint8_t i=0; i<COMPASS_MAX_BACKEND; i++) {
@@ -343,6 +344,10 @@ Compass::_add_backend(AP_Compass_Backend *(detect)(Compass &))
 void 
 Compass::_detect_backends(void)
 {
+    if (_hil_mode) {
+        _add_backend(AP_Compass_HIL::detect);
+        return;
+    }
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_LINUX && CONFIG_HAL_BOARD_SUBTYPE != HAL_BOARD_SUBTYPE_LINUX_NONE
     _add_backend(AP_Compass_HMC5843::detect);
diff --git a/libraries/AP_Compass/Compass.h b/libraries/AP_Compass/Compass.h
index 98667484f4..cc7ca8bfc6 100644
--- a/libraries/AP_Compass/Compass.h
+++ b/libraries/AP_Compass/Compass.h
@@ -246,6 +246,9 @@ public:
     const Vector3f&   getHIL() const;
     void        _setup_earth_field();
 
+    // enable HIL mode
+    void        set_hil_mode(void) { _hil_mode = true; }
+
 
     static const struct AP_Param::GroupInfo var_info[];
 
@@ -331,6 +334,9 @@ private:
         // when we last got data
         uint32_t    last_update_ms;
     } _state[COMPASS_MAX_INSTANCES];
+
+    // if we want HIL only
+    bool _hil_mode:1;
 };
 
 #include "AP_Compass_Backend.h"