flight/pios/stm32f30x/pios_rtc.c

   1 /**
   2  ******************************************************************************
   3  * @addtogroup PIOS PIOS Core hardware abstraction layer
   4  * @{
   5  * @addtogroup   PIOS_RTC RTC Functions
   6  * @brief       Code to manage initialization and interrups of RTC peripheral
   7  * @{
   8  *
   9  * @file       pios_rtc.c
  10  * @author     The LibrePilot Project, http://www.librepilot.org Copyright (C) 2017.
  11  *             The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
  12  * @brief      RTC Functions (STM32 dependent)
  13  * @see        The GNU Public License (GPL) Version 3
  14  *
  15  *****************************************************************************/
  16 /*
  17  * This program is free software; you can redistribute it and/or modify
  18  * it under the terms of the GNU General Public License as published by
  19  * the Free Software Foundation; either version 3 of the License, or
  20  * (at your option) any later version.
  21  *
  22  * This program is distributed in the hope that it will be useful, but
  23  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  24  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  25  * for more details.
  26  *
  27  * You should have received a copy of the GNU General Public License along
  28  * with this program; if not, write to the Free Software Foundation, Inc.,
  29  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  30  */
  31
  32 #include "pios.h"
  33
  34 #ifdef PIOS_INCLUDE_RTC
  35
  36 #include <pios_rtc_priv.h>
  37
  38 #ifndef PIOS_RTC_PRESCALER
  39 #define PIOS_RTC_PRESCALER 100
  40 #endif
  41
  42 struct rtc_callback_entry {
  43     void     (*fn)(uint32_t);
  44     uint32_t data;
  45 };
  46
  47 #define PIOS_RTC_MAX_CALLBACKS 3
  48 struct rtc_callback_entry rtc_callback_list[PIOS_RTC_MAX_CALLBACKS];
  49 static uint8_t rtc_callback_next = 0;
  50
  51 void PIOS_RTC_Init(const struct pios_rtc_cfg *cfg)
  52 {
  53     RCC_BackupResetCmd(ENABLE);
  54     RCC_BackupResetCmd(DISABLE);
  55     RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);
  56     PWR_BackupAccessCmd(ENABLE);
  57     // Divide external 8 MHz clock to 1 MHz
  58     RCC_RTCCLKConfig(cfg->clksrc);
  59     RCC_RTCCLKCmd(ENABLE);
  60
  61     RTC_WakeUpCmd(DISABLE);
  62     // Divide 1 Mhz clock by 16 -> 62.5 khz
  63     RTC_WakeUpClockConfig(RTC_WakeUpClock_RTCCLK_Div16);
  64     // Divide 62.5 khz by 200 to get 625 Hz
  65     RTC_SetWakeUpCounter(cfg->prescaler); // cfg->prescaler);
  66     RTC_WakeUpCmd(ENABLE);
  67
  68     /* Configure and enable the RTC Second interrupt */
  69     EXTI_InitTypeDef ExtiInit = {
  70         .EXTI_Line    = EXTI_Line20, // matches above GPIO pin
  71         .EXTI_Mode    = EXTI_Mode_Interrupt,
  72         .EXTI_Trigger = EXTI_Trigger_Rising,
  73         .EXTI_LineCmd = ENABLE,
  74     };
  75     EXTI_Init((EXTI_InitTypeDef *)&ExtiInit);
  76     NVIC_Init((NVIC_InitTypeDef *)&cfg->irq.init);
  77     RTC_ITConfig(RTC_IT_WUT, ENABLE);
  78
  79     RTC_ClearFlag(RTC_FLAG_WUTF);
  80 }
  81
  82 uint32_t PIOS_RTC_Counter()
  83 {
  84     return RTC_GetWakeUpCounter();
  85 }
  86
  87 /* FIXME: This shouldn't use hard-coded clock rates, dividers or prescalers.
  88  *        Should get these from the cfg struct passed to init.
  89  */
  90 float PIOS_RTC_Rate()
  91 {
  92     return (float)(8e6f / 128.0f) / (1 + PIOS_RTC_PRESCALER);
  93 }
  94
  95 float PIOS_RTC_MsPerTick()
  96 {
  97     return 1000.0f / PIOS_RTC_Rate();
  98 }
  99
 100 /* TODO: This needs a mutex around rtc_callbacks[] */
 101 bool PIOS_RTC_RegisterTickCallback(void (*fn)(uint32_t id), uint32_t data)
 102 {
 103     struct rtc_callback_entry *cb;
 104
 105     if (rtc_callback_next >= PIOS_RTC_MAX_CALLBACKS) {
 106         return false;
 107     }
 108
 109     cb       = &rtc_callback_list[rtc_callback_next++];
 110
 111     cb->fn   = fn;
 112     cb->data = data;
 113     return true;
 114 }
 115
 116 void PIOS_RTC_irq_handler(void)
 117 {
 118     if (RTC_GetITStatus(RTC_IT_WUT)) {
 119         /* Call all registered callbacks */
 120         for (uint8_t i = 0; i < rtc_callback_next; i++) {
 121             struct rtc_callback_entry *cb = &rtc_callback_list[i];
 122             if (cb->fn) {
 123                 (cb->fn)(cb->data);
 124             }
 125         }
 126
 127         /* Clear the RTC Second interrupt */
 128         RTC_ClearITPendingBit(RTC_IT_WUT);
 129     }
 130
 131     if (EXTI_GetITStatus(EXTI_Line20) != RESET) {
 132         EXTI_ClearITPendingBit(EXTI_Line20);
 133     }
 134 }
 135
 136 #endif /* PIOS_INCLUDE_RTC */
 137
 138 /**
 139  * @}
 140  * @}
 141  */