From 5385f25868b4b1ef6577516101fb8bb033f7dfc8 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Tue, 17 Nov 2020 08:40:45 +1100
Subject: [PATCH] AP_RSSI: handle init ordering with MSP

this fixes a nullptr dereference on startup when MSP asks for RSSI
data before the RSSI library is initialised

Fixes #15824
---
 libraries/AP_RSSI/AP_RSSI.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libraries/AP_RSSI/AP_RSSI.cpp b/libraries/AP_RSSI/AP_RSSI.cpp
index 878527366c..e834fa986d 100644
--- a/libraries/AP_RSSI/AP_RSSI.cpp
+++ b/libraries/AP_RSSI/AP_RSSI.cpp
@@ -167,6 +167,9 @@ uint8_t AP_RSSI::read_receiver_rssi_uint8()
 // read the RSSI value from an analog pin - returns float in range 0.0 to 1.0
 float AP_RSSI::read_pin_rssi()
 {
+    if (!rssi_analog_source) {
+        return 0;
+    }
     rssi_analog_source->set_pin(rssi_analog_pin);
     float current_analog_voltage = rssi_analog_source->voltage_average();