AP_Mount: add Backend_Serial

libraries/AP_Mount/AP_Mount_Backend_Serial.cpp

@@ -0,0 +1,24 @@
+#include "AP_Mount_Backend_Serial.h"
+
+#if HAL_MOUNT_ENABLED
+#include <AP_SerialManager/AP_SerialManager.h>
+
+// Default init function for every mount
+void AP_Mount_Backend_Serial::init()
+{
+    const AP_SerialManager& serial_manager = AP::serialmanager();
+
+    // search for serial port.  hild classes should check that uart is not nullptr
+    _uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Gimbal, _serial_instance);
+    if (_uart == nullptr) {
+        return;
+    }
+
+    // initialised successfully if uart is found
+    _initialised = true;
+
+    // call the parent class init
+    AP_Mount_Backend::init();
+}
+
+#endif // HAL_MOUNT_ENABLED

libraries/AP_Mount/AP_Mount_Backend_Serial.h

@@ -0,0 +1,48 @@
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+  Mount driver backend class for serial drivers
+  Mounts using custom serial protocols should be derived from this class
+ */
+#pragma once
+
+#include "AP_Mount_config.h"
+
+#if HAL_MOUNT_ENABLED
+
+#include "AP_Mount_Backend.h"
+
+class AP_Mount_Backend_Serial : public AP_Mount_Backend
+{
+public:
+    // Constructor
+    AP_Mount_Backend_Serial(class AP_Mount &frontend, class AP_Mount_Params &params, uint8_t instance, uint8_t serial_instance) :
+        AP_Mount_Backend(frontend, params, instance),
+        _serial_instance(serial_instance)
+    {}
+
+    // perform any required initialisation for this instance
+    void init() override;
+
+protected:
+
+    // internal variables
+    AP_HAL::UARTDriver *_uart;      // uart connected to gimbal
+    uint8_t _serial_instance;       // this instance's serial instance number
+    bool _initialised;              // true if uart has been initialised
+};
+
+#endif // HAL_MOUNT_ENABLED