RTC: add notion of 'quality' for different time sources

Allow use of mesh based time until a GPS time arrives

docs/software/gps-todo.txt

@@ -6,8 +6,6 @@ bin/run.sh --set region 8
 time only mode
 ./bin/run.sh --set gps_operation 3
 
-set time provisionally from net even if we have gps
-
 ublox parsing failure
 
 record power measurements and update spreadsheet

src/gps/GPS.cpp

@@ -1,10 +1,10 @@
 
 #include "GPS.h"
 #include "NodeDB.h"
+#include "RTC.h"
 #include "configuration.h"
 #include "sleep.h"
 #include <assert.h>
-#include "RTC.h"
 
 // If we have a serial GPS port it will not be null
 #ifdef GPS_RX_PIN
@@ -23,10 +23,8 @@ uint8_t GPS::i2cAddress = GPS_I2C_ADDRESS;
 uint8_t GPS::i2cAddress = 0;
 #endif
 
-
 GPS *gps;
 
-
 bool GPS::setup()
 {
     setAwake(true); // Wake GPS power before doing any init
@@ -99,7 +97,8 @@ uint32_t GPS::getSleepTime() const
     uint32_t t = radioConfig.preferences.gps_update_interval;
 
     auto op = getGpsOp();
-    if ((timeSetFromGPS && op == GpsOperation_GpsOpTimeOnly) || (op == GpsOperation_GpsOpDisabled))
+    bool gotTime = (getRTCQuality() >= RTCQualityGPS);
+    if ((gotTime && op == GpsOperation_GpsOpTimeOnly) || (op == GpsOperation_GpsOpDisabled))
         t = UINT32_MAX; // Sleep forever now
 
     if (t == UINT32_MAX)
@@ -148,7 +147,7 @@ void GPS::loop()
         }
 
         // If we've already set time from the GPS, no need to ask the GPS
-        bool gotTime = timeSetFromGPS || lookForTime();
+        bool gotTime = (getRTCQuality() >= RTCQualityGPS) || lookForTime();
         bool gotLoc = lookForLocation();
 
         // We've been awake too long - force sleep
@@ -158,7 +157,7 @@ void GPS::loop()
         // Once we get a location we no longer desperately want an update
         // or if we got a time and we are in GpsOpTimeOnly mode
         // DEBUG_MSG("gotLoc %d, tooLong %d, gotTime %d\n", gotLoc, tooLong, gotTime);
-        if ((gotLoc && timeSetFromGPS) || tooLong || (gotTime && getGpsOp() == GpsOperation_GpsOpTimeOnly)) {
+        if ((gotLoc && gotTime) || tooLong || (gotTime && getGpsOp() == GpsOperation_GpsOpTimeOnly)) {
             if (gotLoc)
                 hasValidLocation = true;
 

src/gps/NMEAGPS.cpp

@@ -45,7 +45,7 @@ The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of s
         t.tm_mon = d.month() - 1;
         t.tm_year = d.year() - 1900;
         t.tm_isdst = false;
-        perhapsSetRTC(t);
+        perhapsSetRTC(RTCQualityGPS, t);
 
         return true;
     } else

src/gps/RTC.cpp

@@ -1,9 +1,14 @@
-#include "configuration.h"
 #include "RTC.h"
+#include "configuration.h"
 #include <sys/time.h>
 #include <time.h>
 
-bool timeSetFromGPS; // We try to set our time from GPS each time we wake from sleep
+static RTCQuality currentQuality = RTCQualityNone;
+
+RTCQuality getRTCQuality()
+{
+    return currentQuality;
+}
 
 // stuff that really should be in in the instance instead...
 static uint32_t
@@ -17,17 +22,17 @@ void readFromRTC()
     if (!gettimeofday(&tv, NULL)) {
         uint32_t now = millis();
 
-        DEBUG_MSG("Read RTC time as %ld (cur millis %u) valid=%d\n", tv.tv_sec, now, timeSetFromGPS);
+        DEBUG_MSG("Read RTC time as %ld (cur millis %u) quality=%d\n", tv.tv_sec, now, currentQuality);
         timeStartMsec = now;
         zeroOffsetSecs = tv.tv_sec;
     }
 }
 
 /// If we haven't yet set our RTC this boot, set it from a GPS derived time
-bool perhapsSetRTC(const struct timeval *tv)
+bool perhapsSetRTC(RTCQuality q, const struct timeval *tv)
 {
-    if (!timeSetFromGPS) {
-        timeSetFromGPS = true;
+    if (q > currentQuality) {
+        currentQuality = q;
         DEBUG_MSG("Setting RTC %ld secs\n", tv->tv_sec);
 #ifndef NO_ESP32
         settimeofday(tv, NULL);
@@ -41,7 +46,7 @@ bool perhapsSetRTC(const struct timeval *tv)
     }
 }
 
-bool perhapsSetRTC(struct tm &t)
+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
@@ -57,7 +62,7 @@ bool perhapsSetRTC(struct tm &t)
         // 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(&tv);
+        return perhapsSetRTC(q, &tv);
     }
 }
 
@@ -68,5 +73,5 @@ uint32_t getTime()
 
 uint32_t getValidTime()
 {
-    return timeSetFromGPS ? getTime() : 0;
+    return (currentQuality >= RTCQualityFromNet) ? getTime() : 0;
 }

src/gps/RTC.h

@@ -4,16 +4,27 @@
 #include "sys/time.h"
 #include <Arduino.h>
 
-extern bool timeSetFromGPS; // We try to set our time from GPS each time we wake from sleep
+enum RTCQuality {
+    /// We haven't had our RTC set yet
+    RTCQualityNone = 0,
+
+    /// Some other node gave us a time we can use
+    RTCQualityFromNet = 1,
+
+    /// Our time is based on our own GPS
+    RTCQualityGPS = 2
+};
+
+RTCQuality getRTCQuality();
 
 /// If we haven't yet set our RTC this boot, set it from a GPS derived time
-bool perhapsSetRTC(const struct timeval *tv);
-bool perhapsSetRTC(struct tm &t);
+bool perhapsSetRTC(RTCQuality q, const struct timeval *tv);
+bool perhapsSetRTC(RTCQuality q, struct tm &t);
 
-/// Return time since 1970 in secs.  Until we have a GPS lock we will be returning time based at zero
+/// Return time since 1970 in secs.  While quality is RTCQualityNone we will be returning time based at zero
 uint32_t getTime();
 
-/// Return time since 1970 in secs.  If we don't have a GPS lock return zero
+/// Return time since 1970 in secs.  If quality is RTCQualityNone return zero
 uint32_t getValidTime();
 
 void readFromRTC();

src/gps/UBloxGPS.cpp

@@ -152,7 +152,7 @@ bool UBloxGPS::lookForTime()
         t.tm_mon = ublox.getMonth(0) - 1;
         t.tm_year = ublox.getYear(0) - 1900;
         t.tm_isdst = false;
-        perhapsSetRTC(t);
+        perhapsSetRTC(RTCQualityGPS, t);
         return true;
     }
 

src/mesh/MeshService.cpp

@@ -140,7 +140,7 @@ void MeshService::handleIncomingPosition(const MeshPacket *mp)
             tv.tv_sec = secs;
             tv.tv_usec = 0;
 
-            perhapsSetRTC(&tv);
+            perhapsSetRTC(RTCQualityFromNet, &tv);
         }
     } else {
         DEBUG_MSG("Ignoring incoming packet - not a position\n");
@@ -151,12 +151,8 @@ int MeshService::handleFromRadio(const MeshPacket *mp)
 {
     powerFSM.trigger(EVENT_RECEIVED_PACKET); // Possibly keep the node from sleeping
 
-    // If it is a position packet, perhaps set our clock (if we don't have a GPS of our own, otherwise wait for that to work)
-    if (!gps->isConnected)
+    // If it is a position packet, perhaps set our clock 
     handleIncomingPosition(mp);
-    else {
-        DEBUG_MSG("Ignoring incoming time, because we have a GPS\n");
-    }
 
     if (mp->which_payload == MeshPacket_decoded_tag && mp->decoded.which_payload == SubPacket_user_tag) {
         mp = handleFromRadioUser(mp);