/*
 * Copyright (C) 2019  Max Regan
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "rtc.h"
#include "stm32l0xx.h"
#include "macros.h"

static void enable_rtc_write()
{
    /*<! Disable write protection */
    RTC->WPR = 0xCA;
    RTC->WPR = 0x53;
}

static void disable_rtc_write()
{
    /*<! Disable write protection */
    RTC->WPR = 0x00;
}

uint32_t bin_to_bcd(uint32_t bin)
{
    uint32_t bcd = 0;
    while (bin > 0) {
        bcd <<= 4;
        bcd |= bin % 10;
        bin /= 10;
    }

    return bcd;
}

void rtc_init()
{
    uint32_t temp = RCC->CSR;

    SET(RCC->CSR, RCC_CSR_RTCRST);
    SET(RCC->APB1ENR, RCC_APB1ENR_PWREN);
    SET(PWR->CR, PWR_CR_DBP);

    /*<! Set RTC input clock to the LSI (low-speed internal 32.768kHz) clock */
    SET(temp, RCC_CSR_LSEON);
    SET_TO(temp, RCC_CSR_RTCSEL, RCC_CSR_RTCSEL_0);
    SET(temp, RCC_CSR_RTCEN);
    RCC->CSR = temp;

    while (!(RCC->CSR & RCC_CSR_LSERDY)) {}

    enable_rtc_write();

    RTC->ISR = RTC_ISR_INIT;
    while (!(RTC->ISR & RTC_ISR_INITF)) {}

    /*<! Set the Clock Prescalers (32.768kHz / 128 / 256 = 1Hz */
    /*<! Set the Async prescaler to the Maximum (divide the clock by 128) */
    SET_TO(RTC->PRER, RTC_PRER_PREDIV_A, RTC_PRER_PREDIV_A);
    /*<! Set the Syncronous scaler (divide the clock by 255 + 1) */
    SET_TO(RTC->PRER, RTC_PRER_PREDIV_S, 255);


    /*<! Load initial date and time */
    // TODO
    /* uint32_t time = 0; */
    /* uint32_t date = 0; */
    /*<! Set the date and time format */
    // TODO: currently defaults to 24hr

    // 12-Hour format
    SET(RTC->CR, RTC_CR_FMT);

    uint32_t time = 0;
    SET(time, RTC_TR_PM);
    SET_TO(time, RTC_TR_HT, 1 << RTC_TR_HT_Pos);
    SET_TO(time, RTC_TR_HU, 2 << RTC_TR_HU_Pos);
    SET_TO(time, RTC_TR_MNT, 5 << RTC_TR_MNT_Pos);
    SET_TO(time, RTC_TR_MNU, 9 << RTC_TR_MNU_Pos);
    SET_TO(time, RTC_TR_ST, 0 << RTC_TR_ST_Pos);
    SET_TO(time, RTC_TR_SU, 0 << RTC_TR_SU_Pos);
    RTC->TR = time;


    CLR(RTC->ISR, RTC_ISR_INIT);

    disable_rtc_write();
}


void rtc_get_time_bcd(struct time_bcd *tm_bcd)
{
    uint32_t time = RTC->TR;

    tm_bcd->hour_tens = STM32_GET_FIELD(time, RTC_TR_HT);
    tm_bcd->hour_ones = STM32_GET_FIELD(time, RTC_TR_HU);

    tm_bcd->minute_tens = STM32_GET_FIELD(time, RTC_TR_MNT);
    tm_bcd->minute_ones = STM32_GET_FIELD(time, RTC_TR_MNU);

    tm_bcd->second_tens = STM32_GET_FIELD(time, RTC_TR_ST);
    tm_bcd->second_ones = STM32_GET_FIELD(time, RTC_TR_SU);

    tm_bcd->pm = STM32_GET_FIELD(time, RTC_TR_PM);
}