AP_HAL: Add interface for I2CDevice

This is a new interface to replace I2CDriver in future, when all drivers
are converted.

libraries/AP_HAL/AP_HAL_Namespace.h

@@ -12,6 +12,8 @@ namespace AP_HAL {
 
     /* Toplevel class names for drivers: */
     class UARTDriver;
+    class I2CDevice;
+    class I2CDeviceManager;
     class I2CDriver;
     class Device;
 

libraries/AP_HAL/I2CDevice.h

@@ -0,0 +1,74 @@
+/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+/*
+ * Copyright (C) 2015-2016  Intel Corporation. All rights reserved.
+ *
+ * This file 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 file 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/>.
+ */
+#pragma once
+
+#include <inttypes.h>
+
+#include "AP_HAL_Namespace.h"
+#include "Device.h"
+#include "utility/OwnPtr.h"
+
+namespace AP_HAL {
+
+class I2CDevice : public Device {
+public:
+    virtual ~I2CDevice() { }
+
+    /*
+     * Change device address. Note that this is the 7 bit address, it
+     * does not include the bit for read/write.
+     */
+    virtual void set_address(uint8_t address) = 0;
+
+    /* set number of retries on transfers */
+    virtual void set_retries(uint8_t retries) = 0;
+
+    /* Device implementation */
+
+    /* See Device::set_speed() */
+    virtual bool set_speed(Device::Speed speed) override = 0;
+
+    /* See Device::transfer() */
+    virtual bool transfer(const uint8_t *send, uint32_t send_len,
+                          uint8_t *recv, uint32_t recv_len) override = 0;
+
+    /*
+     * Read location from device multiple times, advancing the buffer each
+     * time
+     */
+    virtual bool read_registers_multiple(uint8_t first_reg, uint8_t *recv,
+                                         uint32_t recv_len, uint8_t times) = 0;
+
+    /* See Device::get_semaphore() */
+    virtual Semaphore *get_semaphore() override = 0;
+
+    /* See Device::register_periodic_callback() */
+    virtual Device::PeriodicHandle *register_periodic_callback(
+        uint32_t period_usec, MemberProc) override = 0;
+
+    /* See Device::get_fd() */
+    virtual int get_fd() override = 0;
+};
+
+class I2CDeviceManager {
+public:
+    /* Get a device handle */
+    virtual OwnPtr<AP_HAL::I2CDevice> get_device(uint8_t bus, uint8_t address) = 0;
+};
+
+}