From cd1939a14ed4144917b79e3afb103b5c7d593043 Mon Sep 17 00:00:00 2001
From: Daniel Agar <daniel@agar.ca>
Date: Sun, 9 Oct 2022 12:30:11 -0400
Subject: [PATCH] platforms/common/i2c.cpp: px4_i2c_bus_external check bus
 validity

---
 platforms/common/i2c.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/platforms/common/i2c.cpp b/platforms/common/i2c.cpp
index 7f68a9cfcd..59d4cd3399 100644
--- a/platforms/common/i2c.cpp
+++ b/platforms/common/i2c.cpp
@@ -40,9 +40,11 @@
 #ifndef BOARD_OVERRIDE_I2C_BUS_EXTERNAL
 bool px4_i2c_bus_external(int bus)
 {
-	for (int i = 0; i < I2C_BUS_MAX_BUS_ITEMS; ++i) {
-		if (px4_i2c_buses[i].bus == bus) {
-			return px4_i2c_buses[i].is_external;
+	if (px4_i2c_buses) {
+		for (int i = 0; i < I2C_BUS_MAX_BUS_ITEMS; ++i) {
+			if ((px4_i2c_buses[i].bus != -1) && (px4_i2c_buses[i].bus == bus)) {
+				return px4_i2c_buses[i].is_external;
+			}
 		}
 	}