From ba778ead40ddf8f1282e78cc8b5dd42e6c4fe1c5 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Sun, 26 Dec 2021 11:39:12 +0100
Subject: max44009: handle overrange condition

---
 include/driver/max44009.h | 3 +++
 src/driver/max44009.cc    | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/driver/max44009.h b/include/driver/max44009.h
index cca142f..da64712 100644
--- a/include/driver/max44009.h
+++ b/include/driver/max44009.h
@@ -2,6 +2,9 @@
  * Copyright 2020 Daniel Friesel
  *
  * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Driver for MAX44009 Ambient Light Sensor.
+ * Does not support interrupts.
  */
 #ifndef MAX44009_H
 #define MAX44009_H
diff --git a/src/driver/max44009.cc b/src/driver/max44009.cc
index bab4da5..8a8ff3e 100644
--- a/src/driver/max44009.cc
+++ b/src/driver/max44009.cc
@@ -2,6 +2,9 @@
  * Copyright 2020 Daniel Friesel
  *
  * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Driver for MAX44009 Ambient Light Sensor.
+ * Does not support interrupts.
  */
 #include "driver/max44009.h"
 #if defined(MULTIPASS_ARCH_HAS_I2C) && !defined(CONFIG_driver_softi2c)
@@ -37,6 +40,11 @@ float MAX44009::getLux()
 	*/
 	exponent = (luxHigh & 0xF0) >> 4;
 
+	if (exponent == 0x0f) {
+		// overrange condition
+		return -1;
+	}
+
 	/*
 	* Cast base and mantissa to float to avoid calculation errors
 	* because of 16bit integer overflows.
-- 
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