drivers/distance_sensor/lightware_laser_serial: add LW20/C support

src/drivers/distance_sensor/lightware_laser_serial/lightware_laser_serial.cpp

@@ -127,6 +127,13 @@ LightwareLaserSerial::init()
 		_simple_serial = true;
 		break;
 
+	case 8:
+		/* LW20/c (100M 20Hz) */
+		_px4_rangefinder.set_min_distance(0.2f);
+		_px4_rangefinder.set_max_distance(100.0f);
+		_interval = 50000;
+		break;
+
 	default:
 		PX4_ERR("invalid HW model %" PRIi32 ".", hw_model);
 		return -1;
@@ -297,6 +304,12 @@ void LightwareLaserSerial::Run()
 		if ((termios_state = tcsetattr(_fd, TCSANOW, &uart_config)) < 0) {
 			PX4_ERR("baud %d ATTR", termios_state);
 		}
+
+		// LW20: Enable serial mode by sending some characters
+		if (hw_model == 8) {
+			const char *data = "www\r\n";
+			(void)!::write(_fd, &data, strlen(data));
+		}
 	}
 
 	/* collection phase? */

src/drivers/distance_sensor/lightware_laser_serial/parameters.c

@@ -41,5 +41,8 @@
  * @value 3 SF10/b
  * @value 4 SF10/c
  * @value 5 SF11/c
+ * @value 6 SF30/b
+ * @value 7 SF30/c
+ * @value 8 LW20/c
  */
 PARAM_DEFINE_INT32(SENS_EN_SF0X, 1);