diff --git a/libraries/AP_HAL_Empty/GPIO.cpp b/libraries/AP_HAL_Empty/GPIO.cpp
index 862e3772ef..d8053ac094 100644
--- a/libraries/AP_HAL_Empty/GPIO.cpp
+++ b/libraries/AP_HAL_Empty/GPIO.cpp
@@ -12,12 +12,6 @@ void GPIO::init()
 void GPIO::pinMode(uint8_t pin, uint8_t output)
 {}
 
-int8_t GPIO::analogPinToDigitalPin(uint8_t pin)
-{
-	return -1;
-}
-
-
 uint8_t GPIO::read(uint8_t pin) {
     return 0;
 }
diff --git a/libraries/AP_HAL_Empty/GPIO.h b/libraries/AP_HAL_Empty/GPIO.h
index 740220d749..dc01d34761 100644
--- a/libraries/AP_HAL_Empty/GPIO.h
+++ b/libraries/AP_HAL_Empty/GPIO.h
@@ -7,7 +7,6 @@ public:
     GPIO();
     void    init();
     void    pinMode(uint8_t pin, uint8_t output);
-    int8_t  analogPinToDigitalPin(uint8_t pin);
     uint8_t read(uint8_t pin);
     void    write(uint8_t pin, uint8_t value);
     void    toggle(uint8_t pin);