/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup   PIOS_PWM PWM Input Functions
 * @brief       Code to measure with PWM input
 * @{
 *
 * @file       pios_pwm.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
 * @brief      PWM Input functions (STM32 dependent)
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program 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 program 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, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_RTC

#include <pios_rtc_priv.h>

#ifndef PIOS_RTC_PRESCALER
#define PIOS_RTC_PRESCALER 100
#endif

struct rtc_callback_entry {
    void     (*fn)(uint32_t);
    uint32_t data;
};

#define PIOS_RTC_MAX_CALLBACKS 3
struct rtc_callback_entry rtc_callback_list[PIOS_RTC_MAX_CALLBACKS];
static uint8_t rtc_callback_next = 0;

void PIOS_RTC_Init(const struct pios_rtc_cfg *cfg)
{
    RCC_BackupResetCmd(ENABLE);
    RCC_BackupResetCmd(DISABLE);
    PWR_BackupAccessCmd(ENABLE);
    // Divide external 8 MHz clock to 1 MHz
    RCC_RTCCLKConfig(cfg->clksrc);
    RCC_RTCCLKCmd(ENABLE);

    RTC_WakeUpCmd(DISABLE);
    // Divide 1 Mhz clock by 16 -> 62.5 khz
    RTC_WakeUpClockConfig(RTC_WakeUpClock_RTCCLK_Div16);
    // Divide 62.5 khz by 200 to get 625 Hz
    RTC_SetWakeUpCounter(cfg->prescaler); // cfg->prescaler);
    RTC_WakeUpCmd(ENABLE);

    /* Configure and enable the RTC Second interrupt */
    EXTI_InitTypeDef ExtiInit = {
        .EXTI_Line    = EXTI_Line22, // matches above GPIO pin
        .EXTI_Mode    = EXTI_Mode_Interrupt,
        .EXTI_Trigger = EXTI_Trigger_Rising,
        .EXTI_LineCmd = ENABLE,
    };
    EXTI_Init(&ExtiInit);
    NVIC_Init(&cfg->irq.init);
    RTC_ITConfig(RTC_IT_WUT, ENABLE);

    RTC_ClearFlag(RTC_FLAG_WUTF);
}

uint32_t PIOS_RTC_Counter()
{
    return RTC_GetWakeUpCounter();
}

/* FIXME: This shouldn't use hard-coded clock rates, dividers or prescalers.
 *        Should get these from the cfg struct passed to init.
 */
float PIOS_RTC_Rate()
{
    return (float)(8e6f / 128.0f) / (1 + PIOS_RTC_PRESCALER);
}

float PIOS_RTC_MsPerTick()
{
    return 1000.0f / PIOS_RTC_Rate();
}

/* TODO: This needs a mutex around rtc_callbacks[] */
bool PIOS_RTC_RegisterTickCallback(void (*fn)(uint32_t id), uint32_t data)
{
    struct rtc_callback_entry *cb;

    if (rtc_callback_next >= PIOS_RTC_MAX_CALLBACKS) {
        return false;
    }

    cb       = &rtc_callback_list[rtc_callback_next++];

    cb->fn   = fn;
    cb->data = data;
    return true;
}

void PIOS_RTC_irq_handler(void)
{
    if (RTC_GetITStatus(RTC_IT_WUT)) {
        /* Call all registered callbacks */
        for (uint8_t i = 0; i < rtc_callback_next; i++) {
            struct rtc_callback_entry *cb = &rtc_callback_list[i];
            if (cb->fn) {
                (cb->fn)(cb->data);
            }
        }

        /* Clear the RTC Second interrupt */
        RTC_ClearITPendingBit(RTC_IT_WUT);
    }

    if (EXTI_GetITStatus(EXTI_Line22) != RESET) {
        EXTI_ClearITPendingBit(EXTI_Line22);
    }
}

#endif /* PIOS_INCLUDE_RTC */

/**
 * @}
 * @}
 */