Allow negative differential pressure if parameter enabled (#24434)

src/drivers/differential_pressure/sdp3x/SDP3X.cpp

@@ -32,6 +32,7 @@
  ****************************************************************************/
 
 #include "SDP3X.hpp"
+#include <parameters/param.h>
 
 using namespace time_literals;
 
@@ -187,6 +188,14 @@ int SDP3X::collect()
 	differential_pressure.timestamp_sample = timestamp_sample;
 	differential_pressure.device_id = get_device_id();
 	differential_pressure.differential_pressure_pa = diff_press_pa;
+	int32_t differential_press_rev = 0;
+	param_get(param_find("SENS_DPRES_REV"), &differential_press_rev);
+
+	//If differential pressure reverse param set, swap positive and negative
+	if (differential_press_rev == 1) {
+		differential_pressure.differential_pressure_pa = -1.0f * diff_press_pa;
+	}
+
 	differential_pressure.temperature = temperature_c;
 	differential_pressure.error_count = perf_event_count(_comms_errors);
 	differential_pressure.timestamp = hrt_absolute_time();