firmware/src/gps/RTC.cpp

#include "RTC.h"
#include "configuration.h"
#include "main.h"
#include <sys/time.h>
#include <time.h>

static RTCQuality currentQuality = RTCQualityNone;

RTCQuality getRTCQuality()
{
    return currentQuality;
}

// stuff that really should be in in the instance instead...
static uint32_t
    timeStartMsec; // Once we have a GPS lock, this is where we hold the initial msec clock that corresponds to that time
static uint64_t zeroOffsetSecs; // GPS based time in secs since 1970 - only updated once on initial lock

void readFromRTC()
{
    struct timeval tv; /* btw settimeofday() is helpfull here too*/
#ifdef RV3028_RTC
    if(rtc_found == RV3028_RTC) {
        uint32_t now = millis();
        Melopero_RV3028 rtc;
        rtc.initI2C();
        tm t;
        t.tm_year = rtc.getYear() - 1900;
        t.tm_mon = rtc.getMonth() - 1;
        t.tm_mday = rtc.getDate();
        t.tm_hour = rtc.getHour();
        t.tm_min = rtc.getMinute();
        t.tm_sec = rtc.getSecond();
        tv.tv_sec = mktime(&t);
        tv.tv_usec = 0;
        DEBUG_MSG("Read RTC time from RV3028 as %ld\n", tv.tv_sec);
        timeStartMsec = now;
        zeroOffsetSecs = tv.tv_sec;
        if (currentQuality == RTCQualityNone) {
            currentQuality = RTCQualityDevice;
        }
    }
#elif defined(PCF8563_RTC)
    if(rtc_found == PCF8563_RTC) {
        uint32_t now = millis();
        PCF8563_Class rtc;
#ifdef RTC_USE_WIRE1
        rtc.begin(Wire1);
#else
        rtc.begin();
#endif
        auto tc = rtc.getDateTime();
        tm t;
        t.tm_year = tc.year - 1900;
        t.tm_mon = tc.month - 1;
        t.tm_mday = tc.day;
        t.tm_hour = tc.hour;
        t.tm_min = tc.minute;
        t.tm_sec = tc.second;
        tv.tv_sec = mktime(&t);
        tv.tv_usec = 0;
        DEBUG_MSG("Read RTC time from PCF8563 as %ld\n", tv.tv_sec);
        timeStartMsec = now;
        zeroOffsetSecs = tv.tv_sec;
        if (currentQuality == RTCQualityNone) {
            currentQuality = RTCQualityDevice;
        }
    }
#else 
    if (!gettimeofday(&tv, NULL)) {
        uint32_t now = millis();
        DEBUG_MSG("Read RTC time as %ld\n", tv.tv_sec);
        timeStartMsec = now;
        zeroOffsetSecs = tv.tv_sec;
    }
#endif
}

/// If we haven't yet set our RTC this boot, set it from a GPS derived time
bool perhapsSetRTC(RTCQuality q, const struct timeval *tv)
{
    static uint32_t lastSetMsec = 0;
    uint32_t now = millis();

    bool shouldSet;
    if (q > currentQuality) {
        currentQuality = q;
        shouldSet = true;
        DEBUG_MSG("Upgrading time to RTC %ld secs (quality %d)\n", tv->tv_sec, q);
    } else if(q == RTCQualityGPS && (now - lastSetMsec) > (12 * 60 * 60 * 1000UL)) {
        // Every 12 hrs we will slam in a new GPS time, to correct for local RTC clock drift
        shouldSet = true;
        DEBUG_MSG("Reapplying external time to correct clock drift %ld secs\n", tv->tv_sec);
    }
    else
        shouldSet = false;

    if (shouldSet) {
        lastSetMsec = now;

        // This delta value works on all platforms
        timeStartMsec = now;
        zeroOffsetSecs = tv->tv_sec;

        // If this platform has a setable RTC, set it
#ifdef RV3028_RTC
        if(rtc_found == RV3028_RTC) {
            Melopero_RV3028 rtc;
            rtc.initI2C();
            tm *t = localtime(&tv->tv_sec);
            rtc.setTime(t->tm_year + 1900, t->tm_mon + 1, t->tm_wday, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
            DEBUG_MSG("RV3028_RTC setTime %02d-%02d-%02d %02d:%02d:%02d %ld\n", t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, tv->tv_sec);
        }
#elif defined(PCF8563_RTC)
        if(rtc_found == PCF8563_RTC) {
            PCF8563_Class rtc;
#ifdef RTC_USE_WIRE1
        rtc.begin(Wire1);
#else
        rtc.begin();
#endif
            tm *t = localtime(&tv->tv_sec);
            rtc.setDateTime(t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec);
            DEBUG_MSG("PCF8563_RTC setDateTime %02d-%02d-%02d %02d:%02d:%02d %ld\n", t->tm_year + 1900, t->tm_mon + 1, t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, tv->tv_sec);
        }
#elif defined(ARCH_ESP32)
        settimeofday(tv, NULL);
#endif

        // nrf52 doesn't have a readable RTC (yet - software not written)
#ifdef HAS_RTC
        readFromRTC();
#endif

        return true;
    } else {
        return false;
    }
}

bool perhapsSetRTC(RTCQuality q, struct tm &t)
{
    /* Convert to unix time
    The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970
    (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z).
    */
    time_t res = mktime(&t);
    struct timeval tv;
    tv.tv_sec = res;
    tv.tv_usec = 0; // time.centisecond() * (10 / 1000);

    // DEBUG_MSG("Got time from GPS month=%d, year=%d, unixtime=%ld\n", t.tm_mon, t.tm_year, tv.tv_sec);
    if (t.tm_year < 0 || t.tm_year >= 300) {
        // DEBUG_MSG("Ignoring invalid GPS month=%d, year=%d, unixtime=%ld\n", t.tm_mon, t.tm_year, tv.tv_sec);
        return false;
    } else {
        return perhapsSetRTC(q, &tv);
    }
}

uint32_t getTime()
{
    return (((uint32_t) millis() - timeStartMsec) / 1000) + zeroOffsetSecs;
}

uint32_t getValidTime(RTCQuality minQuality)
{
    return (currentQuality >= minQuality) ? getTime() : 0;
}