/****************************************************************************
 * include/nuttx/rtc.h
 *
 *   Copyright(C) 2011 Uros Platise. All rights reserved.
 *   Author: Uros Platise <uros.platise@isotel.eu>
 *
 * With extensions, modifications by:
 *
 *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
 *   Author: Gregroy Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES(INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

#ifndef __INCLUDE_NUTTX_RTC_H
#define __INCLUDE_NUTTX_RTC_H

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <stdbool.h>
#include <time.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
/* Configuration ************************************************************/
/* CONFIG_RTC - Enables general support for a hardware RTC.  Specific
 *   architectures may require other specific settings.
 *
 * CONFIG_RTC_DATETIME - There are two general types of RTC:  (1) A simple
 *   battery backed counter that keeps the time when power is down, and (2)
 *   A full date / time RTC the provides the date and time information, often
 *   in BCD format.  If CONFIG_RTC_DATETIME is selected, it specifies this
 *   second kind of RTC. In this case, the RTC is used to "seed" the normal
 *   NuttX timer and the NuttX system timer provides for higher resoution
 *   time.
 *
 * CONFIG_RTC_HIRES - If CONFIG_RTC_DATETIME not selected, then the simple,
 *   battery backed counter is used.  There are two different implementations
 *   of such simple counters based on the time resolution of the counter:
 *   The typical RTC keeps time to resolution of 1 second, usually
 *   supporting a 32-bit time_t value.  In this case, the RTC is used to
 *   "seed" the normal NuttX timer and the NuttX timer provides for higher
 *   resoution time.
 *
 *   If CONFIG_RTC_HIRES is enabled in the NuttX configuration, then the
 *   RTC provides higher resolution time and completely replaces the system
 *   timer for purpose of date and time.
 *
 * CONFIG_RTC_FREQUENCY - If CONFIG_RTC_HIRES is defined, then the frequency
 *   of the high resolution RTC must be provided.  If CONFIG_RTC_HIRES is
 *   not defined, CONFIG_RTC_FREQUENCY is assumed to be one.
 *
 * CONFIG_RTC_ALARM - Enable if the RTC hardware supports setting of an
 *   alarm.  A callback function will be executed when the alarm goes off
 */

#ifdef CONFIG_RTC_HIRES
#  ifdef CONFIG_RTC_DATETIME
#    error "CONFIG_RTC_HIRES and CONFIG_RTC_DATETIME are both defined"
#  endif
#  ifndef CONFIG_RTC_FREQUENCY
#    error "CONFIG_RTC_FREQUENCY is required for CONFIG_RTC_HIRES"
#  endif
#else
#  ifndef CONFIG_RTC_FREQUENCY
#    define CONFIG_RTC_FREQUENCY 1
#  endif
#  if CONFIG_RTC_FREQUENCY != 1
#    error "The low resolution RTC must have frequency 1Hz"
#  endif
#endif

/****************************************************************************
 * Public Types
 ****************************************************************************/
/* The form of an alarm callback */

typedef void (alarmcb_t)(void);

/****************************************************************************
 * Public Variables
 ****************************************************************************/

/* Variable determines the state of the RTC module.
 *
 * After initialization value is set to 'true' if RTC starts successfully.
 * The value can be changed to false also during operation if RTC for
 * some reason fails.
 */

extern volatile bool g_rtc_enabled;

/****************************************************************************
 * Public Functions
 ****************************************************************************/

#undef EXTERN
#if defined(__cplusplus)
#define EXTERN extern "C"
extern "C" {
#else
#define EXTERN extern
#endif

/************************************************************************************
 * Name: up_rtcinitialize
 *
 * Description:
 *   Initialize the hardware RTC per the selected configuration.  This function is
 *   called once during the OS initialization sequence
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno on failure
 *
 ************************************************************************************/

EXTERN int up_rtcinitialize(void);

/************************************************************************************
 * Name: up_rtc_time
 *
 * Description:
 *   Get the current time in seconds.  This is similar to the standard time()
 *   function.  This interface is only required if the low-resolution RTC/counter
 *   hardware implementation selected.  It is only used by the RTOS during
 *   intialization to set up the system time when CONFIG_RTC is set but neither
 *   CONFIG_RTC_HIRES nor CONFIG_RTC_DATETIME are set.
 *
 * Input Parameters:
 *   None
 *
 * Returned Value:
 *   The current time in seconds
 *
 ************************************************************************************/

#ifndef CONFIG_RTC_HIRES
EXTERN time_t up_rtc_time(void);
#endif

/************************************************************************************
 * Name: up_rtc_gettime
 *
 * Description:
 *   Get the current time from the high resolution RTC clock/counter.  This interface
 *   is only supported by the high-resolution RTC/counter hardware implementation.
 *   It is used to replace the system timer.
 *
 * Input Parameters:
 *   tp - The location to return the high resolution time value.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno on failure
 *
 ************************************************************************************/

#ifdef CONFIG_RTC_HIRES
EXTERN int up_rtc_gettime(FAR struct timespec *tp);
#endif

/************************************************************************************
 * Name: up_rtc_getdatetime
 *
 * Description:
 *   Get the current date and time from the date/time RTC.  This interface
 *   is only supported by the date/time RTC hardware implementation.
 *   It is used to replace the system timer.  It is only used by the RTOS during
 *   intialization to set up the system time when CONFIG_RTC and CONFIG_RTC_DATETIME
 *   are selected (and CONFIG_RTC_HIRES is not).
 *
 *   NOTE: Some date/time RTC hardware is capability of sub-second accuracy.  That
 *   sub-second accuracy is lost in this interface.  However, since the system time
 *   is reinitialized on each power-up/reset, there will be no timing inaccuracy in
 *   the long run.
 *
 * Input Parameters:
 *   tp - The location to return the high resolution time value.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno on failure
 *
 ************************************************************************************/

#ifdef CONFIG_RTC_DATETIME
EXTERN int up_rtc_getdatetime(FAR struct tm *tp);
#endif

/************************************************************************************
 * Name: up_rtc_settime
 *
 * Description:
 *   Set the RTC to the provided time.  All RTC implementations must be able to
 *   set their time based on a standard timespec.
 *
 * Input Parameters:
 *   tp - the time to use
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno on failure
 *
 ************************************************************************************/

EXTERN int up_rtc_settime(FAR const struct timespec *tp);

/************************************************************************************
 * Name: up_rtc_setalarm
 *
 * Description:
 *   Set up an alarm.
 *
 * Input Parameters:
 *   tp - the time to set the alarm
 *   callback - the function to call when the alarm expires.
 *
 * Returned Value:
 *   Zero (OK) on success; a negated errno on failure
 *
 ************************************************************************************/

#ifdef CONFIG_RTC_ALARM
EXTERN int up_rtc_setalarm(FAR const struct timespec *tp, alarmcb_t callback);
#endif

#undef EXTERN
#if defined(__cplusplus)
}
#endif

#endif /* __INCLUDE_NUTTX_RTC_H */
