ll40ls: [Wingtra docet] fix for properly resetting v3 and v3hp modules.

Signed-off-by: Claudio Micheli <claudio@auterion.com>

src/drivers/distance_sensor/ll40ls/LidarLiteI2C.cpp

@@ -212,12 +212,33 @@ LidarLiteI2C::measure()
 int
 LidarLiteI2C::reset_sensor()
 {
-	int ret = write_reg(LL40LS_MEASURE_REG, LL40LS_MSRREG_RESET);
+	int ret;
+
+	px4_usleep(15000);
+
+	ret = write_reg(LL40LS_SIG_COUNT_VAL_REG, LL40LS_SIG_COUNT_VAL_MAX);
 
 	if (ret != OK) {
 		return ret;
 	}
 
+	px4_usleep(15000);
+	ret = write_reg(LL40LS_MEASURE_REG, LL40LS_MSRREG_RESET);
+
+
+	if (ret != OK) {
+		uint8_t sig_cnt;
+
+		px4_usleep(15000);
+		ret = read_reg(LL40LS_SIG_COUNT_VAL_REG, sig_cnt);
+
+		if ((ret != OK) || (sig_cnt != LL40LS_SIG_COUNT_VAL_DEFAULT)) {
+			printf("Error: ll40ls reset failure. Exiting!\n");
+			return ret;
+
+		}
+	}
+
 	// wait for sensor reset to complete
 	px4_usleep(50000);
 	ret = write_reg(LL40LS_SIG_COUNT_VAL_REG, LL40LS_SIG_COUNT_VAL_MAX);

src/drivers/distance_sensor/ll40ls/LidarLiteI2C.h

@@ -49,6 +49,7 @@
 /* Configuration Constants */
 static constexpr uint8_t LL40LS_BASEADDR	= 0x62;	/* 7-bit address */
 static constexpr uint8_t LL40LS_BASEADDR_OLD	= 0x42;	/* previous 7-bit address */
+static constexpr uint8_t LL40LS_SIG_COUNT_VAL_DEFAULT = 0x80; /* Default maximum acquisition count */
 
 /* LL40LS Registers addresses */
 static constexpr uint8_t LL40LS_MEASURE_REG	= 0x00;	/* Measure range register */