diff --git a/libraries/AP_HAL_PX4/GPIO.cpp b/libraries/AP_HAL_PX4/GPIO.cpp
index ad78f4bb5e..56756505ca 100644
--- a/libraries/AP_HAL_PX4/GPIO.cpp
+++ b/libraries/AP_HAL_PX4/GPIO.cpp
@@ -91,17 +91,6 @@ void PX4GPIO::pinMode(uint8_t pin, uint8_t output)
     }
 }
 
-int8_t PX4GPIO::analogPinToDigitalPin(uint8_t pin)
-{
-    switch (pin) {
-    case PX4_GPIO_FMU_SERVO_PIN(0) ... PX4_GPIO_FMU_SERVO_PIN(5):
-        // the only pins that can be mapped are the FMU servo rail pins */
-        return pin;
-    }
-    return -1;
-}
-
-
 uint8_t PX4GPIO::read(uint8_t pin) {
     switch (pin) {
 
diff --git a/libraries/AP_HAL_PX4/GPIO.h b/libraries/AP_HAL_PX4/GPIO.h
index 82ebadec4c..9a752b2edb 100644
--- a/libraries/AP_HAL_PX4/GPIO.h
+++ b/libraries/AP_HAL_PX4/GPIO.h
@@ -37,7 +37,6 @@ public:
     PX4GPIO();
     void    init() override;
     void    pinMode(uint8_t pin, uint8_t output) override;
-    int8_t  analogPinToDigitalPin(uint8_t pin) override;
     uint8_t read(uint8_t pin) override;
     void    write(uint8_t pin, uint8_t value) override;
     void    toggle(uint8_t pin) override;