camera_trigger : completely refactor state handling

src/drivers/camera_trigger/camera_trigger_params.c

@@ -98,10 +98,10 @@ PARAM_DEFINE_FLOAT(TRIG_ACT_TIME, 40.0f);
  * Camera trigger mode
  *
  * @value 0 Disable
- * @value 1 On individual commands
+ * @value 1 Time based, on command
  * @value 2 Time based, always on
  * @value 3 Distance based, always on
- * @value 4 Distance, mission controlled
+ * @value 4 Distance based, on command (Survey mode)
  * @min 0
  * @max 4
  * @reboot_required true
@@ -136,3 +136,16 @@ PARAM_DEFINE_INT32(TRIG_PINS, 56);
  * @group Camera trigger
  */
 PARAM_DEFINE_FLOAT(TRIG_DISTANCE, 25.0f);
+
+/**
+ * Camera feedback mode
+ *
+ * Sets the camera feedback mode. This parameter will be moved once we
+ * support better camera feedback.
+ *
+ * @value 0 No camera feedback available
+ * @min 0
+ * @max 1
+ * @group Camera Control
+ */
+PARAM_DEFINE_INT32(CAM_FEEDBACK, 0);