AP_RangeFinder: make BLPing backend use new intermediate class

libraries/AP_RangeFinder/AP_RangeFinder_BLPing.cpp

@@ -14,7 +14,6 @@
  */
 
 #include <AP_HAL/AP_HAL.h>
-#include <AP_SerialManager/AP_SerialManager.h>
 #include <GCS_MAVLink/GCS.h>
 #include "AP_RangeFinder_BLPing.h"
 
@@ -46,29 +45,6 @@
 // 8-n      uint8_t[]   payload         message payload
 // (n+1)-(n+2)  uint16_t    checksum    the sum of all the non-checksum bytes in the message (low byte, high byte)
 
-/* 
-   The constructor also initialises the rangefinder. Note that this
-   constructor is not called until detect() returns true, so we
-   already know that we should setup the rangefinder
-*/
-AP_RangeFinder_BLPing::AP_RangeFinder_BLPing(RangeFinder::RangeFinder_State &_state,
-                                             AP_RangeFinder_Params &_params,
-                                             uint8_t serial_instance) :
-    AP_RangeFinder_Backend(_state, _params)
-{
-    const AP_SerialManager &serial_manager = AP::serialmanager();
-    uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance);
-    if (uart != nullptr) {
-        uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance));
-    }
-}
-
-// detect if a serial port has been setup to accept rangefinder input
-bool AP_RangeFinder_BLPing::detect(uint8_t serial_instance)
-{
-    return AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance) != nullptr;
-}
-
 /*
    update the state of the sensor
 */

libraries/AP_RangeFinder/AP_RangeFinder_BLPing.h

@@ -1,20 +1,14 @@
 #pragma once
 
 #include "RangeFinder.h"
-#include "RangeFinder_Backend.h"
+#include "RangeFinder_Backend_Serial.h"
 
-class AP_RangeFinder_BLPing : public AP_RangeFinder_Backend
+class AP_RangeFinder_BLPing : public AP_RangeFinder_Backend_Serial
 {
 
 public:
 
-    // constructor
-    AP_RangeFinder_BLPing(RangeFinder::RangeFinder_State &_state,
-                          AP_RangeFinder_Params &_params,
-                          uint8_t serial_instance);
-
-    // static detection function
-    static bool detect(uint8_t serial_instance);
+    using AP_RangeFinder_Backend_Serial::AP_RangeFinder_Backend_Serial;
 
     // update state
     void update(void) override;
@@ -54,7 +48,6 @@ private:
         CRC_H
     };
 
-    AP_HAL::UARTDriver *uart;
     uint32_t last_init_ms;      // system time that sensor was last initialised
     uint16_t distance_cm;       // latest distance