Notify: add parachute release tune for Pixhawk

libraries/AP_Notify/AP_Notify.h

@@ -43,6 +43,7 @@ public:
         uint16_t failsafe_battery   : 1;    // 1 if battery failsafe
         uint16_t failsafe_gps       : 1;    // 1 if gps failsafe
         uint16_t arming_failed      : 1;    // 1 if copter failed to arm after user input
+        uint16_t parachute_release  : 1;    // 1 if parachute is being released
 
         // additional flags
         uint16_t external_leds      : 1;    // 1 if external LEDs are enabled (normally only used for copter)

libraries/AP_Notify/ToneAlarm_PX4.cpp

@@ -64,7 +64,8 @@ void ToneAlarm_PX4::update()
     if (_tonealarm_fd == -1) {
         return;
     }
-    
+
+    // check for arming failure
     if(flags.arming_failed != AP_Notify::flags.arming_failed) {
         flags.arming_failed = AP_Notify::flags.arming_failed;
         if(flags.arming_failed) {
@@ -110,6 +111,15 @@ void ToneAlarm_PX4::update()
             play_tune(TONE_GPS_WARNING_TUNE);
         }
     }
+
+    // check parachute release
+    if (flags.parachute_release != AP_Notify::flags.parachute_release) {
+        flags.parachute_release = AP_Notify::flags.parachute_release;
+        if (flags.parachute_release) {
+            // parachute release warning tune
+            play_tune(TONE_PARACHUTE_RELEASE_TUNE);
+        }
+    }
 }
 
 #endif // CONFIG_HAL_BOARD == HAL_BOARD_PX4

libraries/AP_Notify/ToneAlarm_PX4.h

@@ -42,6 +42,7 @@ private:
         uint8_t gps_glitching      : 1;    // 1 if gps position is not good
         uint8_t failsafe_gps       : 1;    // 1 if gps failsafe
         uint8_t arming_failed      : 1;    // 0 = failing checks, 1 = passed
+        uint8_t parachute_release  : 1;    // 1 if parachute is being released
     } flags;
 };