PX4Magnetometer: add external() getter and default temperature to NAN

src/lib/drivers/magnetometer/PX4Magnetometer.cpp

@@ -45,6 +45,7 @@ PX4Magnetometer::PX4Magnetometer(uint32_t device_id, uint8_t priority, enum Rota
 
 	_sensor_mag_pub.get().device_id = device_id;
 	_sensor_mag_pub.get().scaling = 1.0f;
+	_sensor_mag_pub.get().temperature = NAN;
 }
 
 PX4Magnetometer::~PX4Magnetometer()
@@ -82,6 +83,9 @@ int PX4Magnetometer::ioctl(cdev::file_t *filp, int cmd, unsigned long arg)
 
 		return 0;
 
+	case MAGIOCGEXTERNAL:
+		return _sensor_mag_pub.get().is_external;
+
 	case DEVIOCGDEVICEID:
 		return _sensor_mag_pub.get().device_id;
 

src/lib/drivers/magnetometer/PX4Magnetometer.hpp

@@ -50,6 +50,8 @@ public:
 
 	int	ioctl(cdev::file_t *filp, int cmd, unsigned long arg) override;
 
+	bool external() { return _sensor_mag_pub.get().is_external; }
+
 	void set_device_type(uint8_t devtype);
 	void set_error_count(uint64_t error_count) { _sensor_mag_pub.get().error_count = error_count; }
 	void increase_error_count() { _sensor_mag_pub.get().error_count++; }