AP_Notify: add singleton

libraries/AP_Notify/AP_Notify.cpp

@@ -32,6 +32,8 @@
 #include "DiscoLED.h"
 #include <stdio.h>
 
+AP_Notify *AP_Notify::_instance;
+
 #define CONFIG_NOTIFY_DEVICES_COUNT 5
 
 // table of user settable parameters
@@ -79,6 +81,10 @@ const AP_Param::GroupInfo AP_Notify::var_info[] = {
 AP_Notify::AP_Notify()
 {
 	AP_Param::setup_object_defaults(this, var_info);
+    if (_instance != nullptr) {
+        AP_HAL::panic("AP_Notify must be singleton");
+    }
+    _instance = this;
 }
 
 // static flags, to allow for direct class update from device drivers

libraries/AP_Notify/AP_Notify.h

@@ -43,6 +43,11 @@ public:
     // Constructor
     AP_Notify();   
 
+    // get singleton instance
+    static AP_Notify *instance(void) {
+        return _instance;
+    }
+
     // Oreo LED Themes
     enum Oreo_LED_Theme {
         OreoLED_Disabled        = 0,    // Disabled the OLED driver entirely
@@ -132,6 +137,8 @@ public:
 
 private:
 
+    static AP_Notify *_instance;
+
     // parameters
     AP_Int8 _rgb_led_brightness;
     AP_Int8 _rgb_led_override;