diff --git a/src/drivers/drv_pwm_output.h b/src/drivers/drv_pwm_output.h
index 76fa35dbf7..099f1c945a 100644
--- a/src/drivers/drv_pwm_output.h
+++ b/src/drivers/drv_pwm_output.h
@@ -244,6 +244,20 @@ struct pwm_output_rc_config {
 /** set SBUS output frame rate in Hz */
 #define PWM_SERVO_SET_SBUS_RATE			_PX4_IOC(_PWM_SERVO_BASE, 31)
 
+/** set auxillary output mode. These correspond to enum Mode in px4fmu/fmu.cpp */
+#define PWM_SERVO_MODE_NONE			0
+#define PWM_SERVO_MODE_2PWM			1
+#define PWM_SERVO_MODE_2PWM2CAP			2
+#define PWM_SERVO_MODE_3PWM			3
+#define PWM_SERVO_MODE_3PWM1CAP			4
+#define PWM_SERVO_MODE_4PWM			5
+#define PWM_SERVO_MODE_6PWM			6
+#define PWM_SERVO_MODE_8PWM			7
+#define PWM_SERVO_MODE_4CAP			8
+#define PWM_SERVO_MODE_5CAP			9
+#define PWM_SERVO_MODE_6CAP		       10
+#define PWM_SERVO_SET_MODE			_PX4_IOC(_PWM_SERVO_BASE, 32)
+
 /*
  *
  *