Lidar lite driver: Fix use of topic initialization

src/drivers/ll40ls/LidarLiteI2C.cpp

@@ -62,7 +62,7 @@ LidarLiteI2C::LidarLiteI2C(int bus, const char *path, int address) :
 	_collect_phase(false),
 	_class_instance(-1),
 	_orb_class_instance(-1),
-	_distance_sensor_topic(-1),
+	_distance_sensor_topic(nullptr),
 	_sample_perf(perf_alloc(PC_ELAPSED, "ll40ls_i2c_read")),
 	_comms_errors(perf_alloc(PC_COUNT, "ll40ls_i2c_comms_errors")),
 	_buffer_overflows(perf_alloc(PC_COUNT, "ll40ls_buffer_i2c_overflows")),
@@ -132,7 +132,7 @@ int LidarLiteI2C::init()
 		_distance_sensor_topic = orb_advertise_multi(ORB_ID(distance_sensor), &ds_report,
 							     &_orb_class_instance, ORB_PRIO_LOW);
 
-		if (_distance_sensor_topic < 0) {
+		if (_distance_sensor_topic == nullptr) {
 			debug("failed to create distance_sensor object. Did you start uOrb?");
 		}
 	}
@@ -442,7 +442,7 @@ int LidarLiteI2C::collect()
 	report.id = 0;
 
 	/* publish it, if we are the primary */
-	if (_distance_sensor_topic >= 0) {
+	if (_distance_sensor_topic != nullptr) {
 		orb_publish(ORB_ID(distance_sensor), _distance_sensor_topic, &report);
 	}
 
@@ -467,22 +467,6 @@ void LidarLiteI2C::start()
 
 	/* schedule a cycle to start things */
 	work_queue(HPWORK, &_work, (worker_t)&LidarLiteI2C::cycle_trampoline, this, 1);
-
-	/* notify about state change */
-	struct subsystem_info_s info = {
-		true,
-		true,
-		true,
-		SUBSYSTEM_TYPE_RANGEFINDER
-	};
-	static orb_advert_t pub = -1;
-
-	if (pub > 0) {
-		orb_publish(ORB_ID(subsystem_info), pub, &info);
-
-	} else {
-		pub = orb_advertise(ORB_ID(subsystem_info), &info);
-	}
 }
 
 void LidarLiteI2C::stop()

src/drivers/ll40ls/LidarLiteI2C.h

@@ -51,7 +51,7 @@
 
 #include <uORB/uORB.h>
 #include <uORB/topics/distance_sensor.h>
-#include <uORB/topics/subsystem_info.h>
+ 
 
 /* Configuration Constants */
 #define LL40LS_BUS          PX4_I2C_BUS_EXPANSION

src/drivers/ll40ls/LidarLitePWM.cpp

@@ -61,7 +61,7 @@ LidarLitePWM::LidarLitePWM(const char *path) :
 	_orb_class_instance(-1),
 	_pwmSub(-1),
 	_pwm{},
-	_distance_sensor_topic(-1),
+	_distance_sensor_topic(nullptr),
 	_range{},
 	_sample_perf(perf_alloc(PC_ELAPSED, "ll40ls_pwm_read")),
 	_read_errors(perf_alloc(PC_COUNT, "ll40ls_pwm_read_errors")),
@@ -116,7 +116,7 @@ int LidarLitePWM::init()
 		_distance_sensor_topic = orb_advertise_multi(ORB_ID(distance_sensor), &ds_report,
 							     &_orb_class_instance, ORB_PRIO_LOW);
 
-		if (_distance_sensor_topic < 0) {
+		if (_distance_sensor_topic == nullptr) {
 			debug("failed to create distance_sensor object. Did you start uOrb?");
 		}
 	}
@@ -198,7 +198,7 @@ int LidarLitePWM::measure()
 		return reset_sensor();
 	}
 
-	if (_distance_sensor_topic >= 0) {
+	if (_distance_sensor_topic != nullptr) {
 		orb_publish(ORB_ID(distance_sensor), _distance_sensor_topic, &_range);
 	}