sensor_baro add separate timestamp_sample field

- the timestamp is uORB message publication metadata

msg/sensor_baro.msg

@@ -1,7 +1,9 @@
-uint64 timestamp	# time since system start (microseconds)
-uint32 device_id	# Sensor ID that must be unique for each baro sensor and must not change
+uint64 timestamp          # time since system start (microseconds)
+uint64 timestamp_sample
 
-uint64 error_count
+uint32 device_id          # unique device ID for the sensor that does not change between power cycles
+
+uint32 error_count
 
 float32 pressure	# static pressure measurement in millibar
 

src/lib/drivers/barometer/PX4Barometer.cpp

@@ -55,8 +55,7 @@ PX4Barometer::~PX4Barometer()
 	_sensor_baro_pub.unadvertise();
 }
 
-void
-PX4Barometer::set_device_type(uint8_t devtype)
+void PX4Barometer::set_device_type(uint8_t devtype)
 {
 	// current DeviceStructure
 	union device::Device::DeviceId device_id;
@@ -69,13 +68,12 @@ PX4Barometer::set_device_type(uint8_t devtype)
 	_sensor_baro_pub.get().device_id = device_id.devid;
 }
 
-void
-PX4Barometer::update(hrt_abstime timestamp, float pressure)
+void PX4Barometer::update(const hrt_abstime &timestamp_sample, float pressure)
 {
 	sensor_baro_s &report = _sensor_baro_pub.get();
 
-	report.timestamp = timestamp;
+	report.timestamp_sample = timestamp_sample;
 	report.pressure = pressure;
-
+	report.timestamp = hrt_absolute_time();
 	_sensor_baro_pub.update();
 }

src/lib/drivers/barometer/PX4Barometer.hpp

@@ -55,7 +55,7 @@ public:
 
 	void set_temperature(float temperature) { _sensor_baro_pub.get().temperature = temperature; }
 
-	void update(hrt_abstime timestamp, float pressure);
+	void update(const hrt_abstime &timestamp_sample, float pressure);
 
 	int get_class_instance() { return _class_device_instance; };
 

src/modules/sensors/vehicle_air_data/VehicleAirData.cpp

@@ -200,7 +200,7 @@ void VehicleAirData::Run()
 
 		const sensor_baro_s &baro = _last_data[_selected_sensor_sub_index];
 
-		_baro_timestamp_sum += baro.timestamp;
+		_baro_timestamp_sum += baro.timestamp_sample;
 		_baro_sum += baro.pressure;
 		_baro_sum_count++;
 
@@ -217,7 +217,7 @@ void VehicleAirData::Run()
 
 			// populate vehicle_air_data with primary baro and publish
 			vehicle_air_data_s out{};
-			out.timestamp_sample = timestamp_sample; // TODO: baro.timestamp_sample;
+			out.timestamp_sample = timestamp_sample;
 			out.baro_device_id = baro.device_id;
 			out.baro_temp_celcius = baro.temperature;