From b18f1a8e2269ca13747f04afbc25b780f47b994f Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Fri, 1 Nov 2019 21:35:23 +1100
Subject: [PATCH] AP_RangeFinder: move uLanding to using common serial backend

---
 .../AP_RangeFinder_uLanding.cpp               | 31 -------------------
 .../AP_RangeFinder/AP_RangeFinder_uLanding.h  | 20 ++++++------
 .../RangeFinder_Backend_Serial.cpp            |  2 +-
 .../RangeFinder_Backend_Serial.h              |  4 +++
 4 files changed, 16 insertions(+), 41 deletions(-)

diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.cpp b/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.cpp
index cf7854b120..dc2d13781b 100644
--- a/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.cpp
+++ b/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.cpp
@@ -15,44 +15,13 @@
 
 #include <AP_HAL/AP_HAL.h>
 #include "AP_RangeFinder_uLanding.h"
-#include <AP_SerialManager/AP_SerialManager.h>
 #include <ctype.h>
 
 #define ULANDING_HDR 254   // Header Byte from uLanding (0xFE)
 #define ULANDING_HDR_V0 72 // Header Byte for beta V0 of uLanding (0x48)
 
-#define ULANDING_BAUD           115200
-#define ULANDING_BUFSIZE_RX     128
-#define ULANDING_BUFSIZE_TX     128
-
 extern const AP_HAL::HAL& hal;
 
-/*
-   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_uLanding::AP_RangeFinder_uLanding(RangeFinder::RangeFinder_State &_state,
-                                                 AP_RangeFinder_Params &_params,
-                                                 uint8_t serial_instance) :
-    AP_RangeFinder_Backend(_state, _params)
-{
-    uart = AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance);
-    if (uart != nullptr) {
-        uart->begin(ULANDING_BAUD, ULANDING_BUFSIZE_RX, ULANDING_BUFSIZE_TX);
-    }
-}
-
-/*
-   detect if a uLanding rangefinder is connected. We'll detect by
-   trying to take a reading on Serial. If we get a result the sensor is
-   there.
-*/
-bool AP_RangeFinder_uLanding::detect(uint8_t serial_instance)
-{
-    return AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance) != nullptr;
-}
-
 /*
    detect uLanding Firmware Version
 */
diff --git a/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.h b/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.h
index c76410aab3..3c6c5caf61 100644
--- a/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.h
+++ b/libraries/AP_RangeFinder/AP_RangeFinder_uLanding.h
@@ -1,19 +1,14 @@
 #pragma once
 
 #include "RangeFinder.h"
-#include "RangeFinder_Backend.h"
+#include "RangeFinder_Backend_Serial.h"
 
-class AP_RangeFinder_uLanding : public AP_RangeFinder_Backend
+class AP_RangeFinder_uLanding : public AP_RangeFinder_Backend_Serial
 {
 
 public:
-    // constructor
-	AP_RangeFinder_uLanding(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;
@@ -24,6 +19,14 @@ protected:
         return MAV_DISTANCE_SENSOR_RADAR;
     }
 
+    // baudrate used during object construction:
+    uint32_t initial_baudrate(uint8_t serial_instance) const override {
+        return 115200;
+    }
+
+    uint16_t rx_bufsize() const override { return 128; }
+    uint16_t tx_bufsize() const override { return 128; }
+
 private:
     // detect uLanding Firmware Version
     bool detect_version(void);
@@ -31,7 +34,6 @@ private:
     // get a reading
     bool get_reading(uint16_t &reading_cm);
 
-    AP_HAL::UARTDriver *uart;
     uint8_t  _linebuf[6];
     uint8_t  _linebuf_len;
     bool     _version_known;
diff --git a/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.cpp b/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.cpp
index 01eaee5631..3d8ddb2ed0 100644
--- a/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.cpp
+++ b/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.cpp
@@ -34,7 +34,7 @@ AP_RangeFinder_Backend_Serial::AP_RangeFinder_Backend_Serial(
 {
     uart = AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance);
     if (uart != nullptr) {
-        uart->begin(initial_baudrate(serial_instance));
+        uart->begin(initial_baudrate(serial_instance), rx_bufsize(), tx_bufsize());
     }
 }
 
diff --git a/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.h b/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.h
index 2d2922a736..e8f8b26e37 100644
--- a/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.h
+++ b/libraries/AP_RangeFinder/RangeFinder_Backend_Serial.h
@@ -18,5 +18,9 @@ protected:
     // baudrate used during object construction:
     virtual uint32_t initial_baudrate(uint8_t serial_instance) const;
 
+    // the value 0 is special to the UARTDriver - it's "use default"
+    virtual uint16_t rx_bufsize() const { return 0; }
+    virtual uint16_t tx_bufsize() const { return 0; }
+
     AP_HAL::UARTDriver *uart = nullptr;
 };