mbed-os/drivers/RealTimeClock.h

145 lines
4.1 KiB
C++

/* mbed Microcontroller Library
* Copyright (c) 2006-2019 ARM Limited
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MBED_REALTIMECLOCK_H
#define MBED_REALTIMECLOCK_H
#include <chrono>
#include "hal/rtc_api.h"
namespace mbed {
/**
* \defgroup drivers_RealTimeClock RealTimeClock class
* \ingroup drivers-public-api-ticker
* @{
*/
/**
* An implementation of a C++11 Clock representing the HAL real-time clock.
*
* This is intended to be usable as a substitute for @c std::chrono::system_clock,
* but is provided as a separate class, due to inconsistencies in retargetting
* support between toolchains.
*
* This is only a thin wrapper around the HAL RTC API, and as such it requires the
* same use of initialization.
*
*/
class RealTimeClock {
public:
using duration = std::chrono::seconds;
using rep = duration::rep;
using period = duration::period;
using time_point = std::chrono::time_point<RealTimeClock>;
static const bool is_steady = false;
/** Initialize the RTC peripheral
*
* Power up the RTC in preparation for access. This function must be called
* before any other RealTimeClock methods are called. This does not change the state
* of the RTC. It just enables access to it.
*
* @see ::rtc_init
*/
static void init()
{
return rtc_init();
}
/** Deinitialize RTC
*
* Powerdown the RTC in preparation for sleep, powerdown or reset. That should only
* affect the CPU domain and not the time keeping logic.
* After this function is called no other RealTimeClock methods should be called
* except for RealTimeClock::init.
*
* @see ::rtc_free
*/
static void free()
{
return rtc_free();
}
/** Check if the RTC has the time set and is counting
*
* @retval false The time reported by the RTC is not valid
* @retval true The time has been set and the RTC is counting
*
* @see ::rtc_isenabled
*/
static bool isenabled() noexcept
{
return bool(rtc_isenabled());
}
/** Get the current time from the RTC peripheral
*
* @return The current time in seconds
*
* @see ::rtc_read
*/
static time_point now() noexcept
{
return from_time_t(rtc_read());
}
/** Write the current time in seconds to the RTC peripheral
*
* @param t The current time to be set in seconds.
*
* @see ::rtc_write
*/
static void write(time_point t) noexcept
{
rtc_write(to_time_t(t));
}
/** Convert a C time_t to C++ Chrono time_point
*
* @param t a @c time_t object
* @return a RealTimeClock::time_point object that represents the same point in time as @p t.
*/
static time_point from_time_t(time_t t) noexcept
{
return time_point{std::chrono::duration_cast<duration>(std::chrono::duration<time_t>{t})};
}
/** Convert a C++ Chrono time_point to a C time_t
*
* @param t a RealTimeClock::time_point object
* @return a @c time_t object that represents the same point in time as @p t.
*/
static time_t to_time_t(const time_point &t) noexcept
{
return std::chrono::duration_cast<std::chrono::duration<time_t>>(t.time_since_epoch()).count();
}
/** Lock the clock to ensure it stays running; dummy for API compatibility with HighResClock */
static void lock()
{
}
/** Unlock the clock, allowing it to stop during power saving; dummy for API compatibility with HighResClock */
static void unlock()
{
}
};
/** @}*/
}
#endif /* MBED_TICKERCLOCK_H */