diff --git a/src/platforms/posix/drivers/barosim/baro.cpp b/src/platforms/posix/drivers/barosim/baro.cpp
index 90f0f71efc..91bd149135 100644
--- a/src/platforms/posix/drivers/barosim/baro.cpp
+++ b/src/platforms/posix/drivers/barosim/baro.cpp
@@ -439,10 +439,10 @@ BAROSIM::ioctl(device::file_t *filp, int cmd, unsigned long arg)
 				bool want_start = (_measure_ticks == 0);
 
 				/* convert hz to tick interval via microseconds */
-				unsigned ticks = USEC2TICK(1000000 / arg);
+				unsigned long ticks = USEC2TICK(1000000 / arg);
 
 				/* check against maximum rate */
-				if ((long)ticks < USEC2TICK(BAROSIM_CONVERSION_INTERVAL))
+				if (ticks < USEC2TICK(BAROSIM_CONVERSION_INTERVAL))
 					return -EINVAL;
 
 				/* update interval for next measurement */
@@ -559,7 +559,7 @@ BAROSIM::cycle()
 		 * doing pressure measurements at something close to the desired rate.
 		 */
 		if ((_measure_phase != 0) &&
-		    ((long)_measure_ticks > USEC2TICK(BAROSIM_CONVERSION_INTERVAL))) {
+		    (_measure_ticks > USEC2TICK(BAROSIM_CONVERSION_INTERVAL))) {
 
 			/* schedule a fresh cycle call when we are ready to measure again */
 			work_queue(HPWORK,
diff --git a/src/platforms/px4_defines.h b/src/platforms/px4_defines.h
index 41499e69c7..e123a008c5 100644
--- a/src/platforms/px4_defines.h
+++ b/src/platforms/px4_defines.h
@@ -131,7 +131,7 @@ __BEGIN_DECLS
 extern long PX4_TICKS_PER_SEC;
 __END_DECLS
 
-#define USEC_PER_TICK (1000000L/PX4_TICKS_PER_SEC)
+#define USEC_PER_TICK (1000000UL/PX4_TICKS_PER_SEC)
 #define USEC2TICK(x) (((x)+(USEC_PER_TICK/2))/USEC_PER_TICK) 
 
 #define px4_statfs_buf_f_bavail_t unsigned long