text: /* mbed Microcontroller Library
   *******************************************************************************
   * Copyright (c) 2014, STMicroelectronics
   * All rights reserved.
   *
   * 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 of STMicroelectronics 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 HOLDER 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.
   *******************************************************************************
   */
  #include "rtc_api.h"
  
  #if DEVICE_RTC
  
  #include "mbed_error.h"
  
  #if DEVICE_RTC_LSI
  static int rtc_inited = 0;
  #endif
  
  RTC_HandleTypeDef RtcHandle;
  
  void rtc_init(void)
  {
      RCC_OscInitTypeDef RCC_OscInitStruct;
      uint32_t rtc_freq = 0;
  
  #if DEVICE_RTC_LSI
      if (rtc_inited) return;
      rtc_inited = 1;
  #endif
  
      RtcHandle.Instance = RTC;
  
  #if !DEVICE_RTC_LSI
      // Enable LSE Oscillator
      RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI | RCC_OSCILLATORTYPE_LSE;
      RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; // Mandatory, otherwise the PLL is reconfigured!
      RCC_OscInitStruct.LSEState       = RCC_LSE_ON; // External 32.768 kHz clock on OSC_IN/OSC_OUT
      RCC_OscInitStruct.LSIState       = RCC_LSI_OFF;
      if (HAL_RCC_OscConfig(&RCC_OscInitStruct) == HAL_OK) { // Check if LSE has started correctly
          // Connect LSE to RTC
          __HAL_RCC_RTC_CLKPRESCALER(RCC_RTCCLKSOURCE_LSE);
          __HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSE);
          rtc_freq = LSE_VALUE;
      } else {
  	    error("Cannot initialize RTC with LSE\n");
      }
  #else	
      // Enable Power clock
      __PWR_CLK_ENABLE();
  
      // Enable access to Backup domain
      HAL_PWR_EnableBkUpAccess();
  
      // Reset Backup domain
      __HAL_RCC_BACKUPRESET_FORCE();
      __HAL_RCC_BACKUPRESET_RELEASE();
  
  	// Enable LSI clock
  	RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI | RCC_OSCILLATORTYPE_LSE;
  	RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE; // Mandatory, otherwise the PLL is reconfigured!
  	RCC_OscInitStruct.LSEState       = RCC_LSE_OFF;
  	RCC_OscInitStruct.LSIState       = RCC_LSI_ON;
  	if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) {
  		error("Cannot initialize RTC with LSI\n");
  	}
  	// Connect LSI to RTC
      __HAL_RCC_RTC_CLKPRESCALER(RCC_RTCCLKSOURCE_LSI);
      __HAL_RCC_RTC_CONFIG(RCC_RTCCLKSOURCE_LSI);
  	// This value is LSI typical value. To be measured precisely using a timer input capture for example.
  	rtc_freq = 40000;
  #endif
  
      // Enable RTC
      __HAL_RCC_RTC_ENABLE();
  
      RtcHandle.Init.HourFormat     = RTC_HOURFORMAT_24;
  #ifdef TARGET_MOTE_L152RC
      /* SubSecond resolution of 16384Hz */
      RtcHandle.Init.AsynchPrediv   = 1;
      RtcHandle.Init.SynchPrediv    = (rtc_freq / 2) - 1;
  #else
      RtcHandle.Init.AsynchPrediv   = 127;
      RtcHandle.Init.SynchPrediv    = (rtc_freq / 128) - 1;
  #endif
      RtcHandle.Init.OutPut         = RTC_OUTPUT_DISABLE;
      RtcHandle.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
      RtcHandle.Init.OutPutType     = RTC_OUTPUT_TYPE_OPENDRAIN;
  
      if (HAL_RTC_Init(&RtcHandle) != HAL_OK) {
          error("RTC error: RTC initialization failed.");
      }
  }
  
  void rtc_free(void)
  {
  #if DEVICE_RTC_LSI
      // Enable Power clock
      __PWR_CLK_ENABLE();
  
      // Enable access to Backup domain
      HAL_PWR_EnableBkUpAccess();
  
      // Reset Backup domain
      __HAL_RCC_BACKUPRESET_FORCE();
      __HAL_RCC_BACKUPRESET_RELEASE();
  
      // Disable access to Backup domain
      HAL_PWR_DisableBkUpAccess();
  #endif
  
      // Disable LSI and LSE clocks
      RCC_OscInitTypeDef RCC_OscInitStruct;
      RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_LSI | RCC_OSCILLATORTYPE_LSE;
      RCC_OscInitStruct.PLL.PLLState   = RCC_PLL_NONE;
      RCC_OscInitStruct.LSIState       = RCC_LSI_OFF;
      RCC_OscInitStruct.LSEState       = RCC_LSE_OFF;
      HAL_RCC_OscConfig(&RCC_OscInitStruct);
  
  #if DEVICE_RTC_LSI
      rtc_inited = 0;
  #endif
  }
  
  int rtc_isenabled(void)
  {
  #if DEVICE_RTC_LSI
    return rtc_inited;
  #else
    if ((RTC->ISR & RTC_ISR_INITS) ==  RTC_ISR_INITS) {
      return 1;
    } else {
      return 0;
    }
  #endif
  }
  
  /*
   RTC Registers
     RTC_WeekDay 1=monday, 2=tuesday, ..., 7=sunday
     RTC_Month   1=january, 2=february, ..., 12=december
     RTC_Date    day of the month 1-31
     RTC_Year    year 0-99
   struct tm
     tm_sec      seconds after the minute 0-61
     tm_min      minutes after the hour 0-59
     tm_hour     hours since midnight 0-23
     tm_mday     day of the month 1-31
     tm_mon      months since January 0-11
     tm_year     years since 1900
     tm_wday     days since Sunday 0-6
     tm_yday     days since January 1 0-365
     tm_isdst    Daylight Saving Time flag
  */
  time_t rtc_read(void)
  {
      RTC_DateTypeDef dateStruct;
      RTC_TimeTypeDef timeStruct;
      struct tm timeinfo;
  
      RtcHandle.Instance = RTC;
  
      // Read actual date and time
      // Warning: the time must be read first!
      HAL_RTC_GetTime(&RtcHandle, &timeStruct, FORMAT_BIN);
      HAL_RTC_GetDate(&RtcHandle, &dateStruct, FORMAT_BIN);
  
      // Setup a tm structure based on the RTC
      timeinfo.tm_wday = dateStruct.WeekDay;
      timeinfo.tm_mon  = dateStruct.Month - 1;
      timeinfo.tm_mday = dateStruct.Date;
      timeinfo.tm_year = dateStruct.Year + 100;
      timeinfo.tm_hour = timeStruct.Hours;
      timeinfo.tm_min  = timeStruct.Minutes;
      timeinfo.tm_sec  = timeStruct.Seconds;
      // Daylight Saving Time information is not available
      timeinfo.tm_isdst = -1;
  
      // Convert to timestamp
      time_t t = mktime(&timeinfo);
  
      return t;
  }
  
  void rtc_write(time_t t)
  {
      RTC_DateTypeDef dateStruct;
      RTC_TimeTypeDef timeStruct;
  
      RtcHandle.Instance = RTC;
  
      // Convert the time into a tm
      struct tm *timeinfo = localtime(&t);
  
      // Fill RTC structures
      dateStruct.WeekDay        = timeinfo->tm_wday;
      dateStruct.Month          = timeinfo->tm_mon + 1;
      dateStruct.Date           = timeinfo->tm_mday;
      dateStruct.Year           = timeinfo->tm_year - 100;
      timeStruct.Hours          = timeinfo->tm_hour;
      timeStruct.Minutes        = timeinfo->tm_min;
      timeStruct.Seconds        = timeinfo->tm_sec;
      timeStruct.TimeFormat     = RTC_HOURFORMAT12_PM;
      timeStruct.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
      timeStruct.StoreOperation = RTC_STOREOPERATION_RESET;
  
      // Change the RTC current date/time
      HAL_RTC_SetDate(&RtcHandle, &dateStruct, FORMAT_BIN);
      HAL_RTC_SetTime(&RtcHandle, &timeStruct, FORMAT_BIN);
  }
  
  #endif
  