AP_Mount: Add parameter to control relative pan option for servo mounts

* Change from a dedicated parameter to a reusable options field

libraries/AP_Mount/AP_Mount.cpp

@@ -213,12 +213,13 @@ const AP_Param::GroupInfo AP_Mount::var_info[] = {
 
     // 23 formerly _K_RATE
 
-    // @Param: _REL_PAN
-    // @DisplayName: Relative pan flag for Servo Mount
-    // @Description: Enable to calculate pan angle to GPS location relative to vehicle orientation (for type servo (1))
-    // @Values: 0:Disabled,1:Enabled
+    // @Param: _OPTIONS
+    // @DisplayName: Options field
+    // @Description: User configurable options; 0 = Enable Relative Pan on Servo Mounts
+    // @Values:  0:RelativePan
+    // @Bitmask: 0:RelativePan
     // @User: Standard
-    AP_GROUPINFO("_REL_PAN",        24, AP_Mount, state[0]._rel_pan, 0),
+    AP_GROUPINFO("_OPTIONS",        24, AP_Mount, state[0]._options, 0),
 
 #if AP_MOUNT_MAX_INSTANCES > 1
     // @Param: 2_DEFLT_MODE
@@ -401,12 +402,13 @@ const AP_Param::GroupInfo AP_Mount::var_info[] = {
     // @User: Standard
     AP_GROUPINFO("2_TYPE",           42, AP_Mount, state[1]._type, 0),
 
-    // @Param: 2_REL_PAN
-    // @DisplayName: Relative pan flag for Servo Mount 2
-    // @Description: Enable to calculate pan angle to GPS location relative to vehicle orientation (for type servo (1))
-    // @Values: 0:Disabled,1:Enabled
+    // @Param: 2_OPTIONS
+    // @DisplayName: Options field for Mount 2
+    // @Description: User configurable options; 0 = Enable Relative Pan on Servo Mounts
+    // @Values:  0:RelativePan
+    // @Bitmask: 0:RelativePan
     // @User: Standard
-    AP_GROUPINFO("2_REL_PAN",        43, AP_Mount, state[0]._rel_pan, 0),
+    AP_GROUPINFO("2_OPTIONS",       43, AP_Mount, state[1]._options, 0),
 #endif // AP_MOUNT_MAX_INSTANCES > 1
 
     AP_GROUPEND

libraries/AP_Mount/AP_Mount.h

@@ -40,6 +40,9 @@
 // maximum number of mounts
 #define AP_MOUNT_MAX_INSTANCES          1
 
+// options (see _OPTIONS parameter)
+#define AP_MOUNT_OPTION_RELATIVE_PAN    (1<<0)
+
 // declare backend classes
 class AP_Mount_Backend;
 class AP_Mount_Servo;
@@ -190,7 +193,7 @@ protected:
         Location _target_sysid_location; // sysid target location
         bool _target_sysid_location_set;
 
-        AP_Int8         _rel_pan;           // Use relative pan for servo mounts (0=Disable, 1=Enable)
+        AP_Int8         _options;           // Options field, bit 0 = use relative pan
 
     } state[AP_MOUNT_MAX_INSTANCES];
 

libraries/AP_Mount/AP_Mount_Servo.cpp

@@ -35,6 +35,8 @@ void AP_Mount_Servo::update()
         _last_check_servo_map_ms = now;
     }
 
+    uint8_t relative_pan = _state._options & AP_MOUNT_OPTION_RELATIVE_PAN;
+
     switch(get_mode()) {
         // move mount to a "retracted position" or to a position where a fourth servo can retract the entire mount into the fuselage
         case MAV_MOUNT_MODE_RETRACT:
@@ -70,7 +72,7 @@ void AP_Mount_Servo::update()
         // point mount to a GPS point given by the mission planner
         case MAV_MOUNT_MODE_GPS_POINT:
         {
-            if (calc_angle_to_roi_target(_angle_ef_target_rad, _flags.tilt_control, _flags.pan_control, _state._rel_pan)) {
+            if (calc_angle_to_roi_target(_angle_ef_target_rad, _flags.tilt_control, _flags.pan_control, relative_pan)) {
                 stabilize();
             }
             break;
@@ -83,7 +85,7 @@ void AP_Mount_Servo::update()
             }
             _state._roi_target = AP::ahrs().get_home();
             _state._roi_target_set = true;
-            if (calc_angle_to_roi_target(_angle_ef_target_rad, _flags.tilt_control, _flags.pan_control, _state._rel_pan)) {
+            if (calc_angle_to_roi_target(_angle_ef_target_rad, _flags.tilt_control, _flags.pan_control, relative_pan)) {
                 stabilize();
             }
             break;
@@ -92,7 +94,7 @@ void AP_Mount_Servo::update()
             if (calc_angle_to_sysid_target(_angle_ef_target_rad,
                                            _flags.tilt_control,
                                            _flags.pan_control,
-                                           _state._rel_pan)) {
+                                           relative_pan)) {
                 stabilize();
             }
             break;