From 99f680da57a2115ee0a7c3f4ac42913c297e3f19 Mon Sep 17 00:00:00 2001
From: Theo Arends <11044339+arendst@users.noreply.github.com>
Date: Fri, 5 Jul 2019 11:47:13 +0200
Subject: [PATCH] Add NTP drift information

Add NTP drift information
---
 sonoff/sonoff.ino      | 3 ++-
 sonoff/support_rtc.ino | 7 +++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/sonoff/sonoff.ino b/sonoff/sonoff.ino
index 02ea25524..dd564827a 100755
--- a/sonoff/sonoff.ino
+++ b/sonoff/sonoff.ino
@@ -2013,7 +2013,8 @@ void PerformEverySecond(void)
 
   if (ntp_synced_message) {
     // Moved here to fix syslog UDP exception 9 during RtcSecond
-    AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_APPLICATION "(" D_UTC_TIME ") %s, (" D_DST_TIME ") %s, (" D_STD_TIME ") %s"), GetTime(0).c_str(), GetTime(2).c_str(), GetTime(3).c_str());
+    AddLog_P2(LOG_LEVEL_DEBUG, PSTR("NTP: Drift %d, (" D_UTC_TIME ") %s, (" D_DST_TIME ") %s, (" D_STD_TIME ") %s"),
+      DriftTime(), GetTime(0).c_str(), GetTime(2).c_str(), GetTime(3).c_str());
     ntp_synced_message = false;
   }
 
diff --git a/sonoff/support_rtc.ino b/sonoff/support_rtc.ino
index 03efeb510..e55bff4c5 100644
--- a/sonoff/support_rtc.ino
+++ b/sonoff/support_rtc.ino
@@ -46,10 +46,16 @@ uint32_t standard_time = 0;
 uint32_t ntp_time = 0;
 uint32_t midnight = 0;
 uint32_t restart_time = 0;
+int32_t  drift_time = 0;
 int32_t  time_timezone = 0;
 uint8_t  midnight_now = 0;
 uint8_t  ntp_sync_minute = 0;
 
+int32_t DriftTime(void)
+{
+  return drift_time;
+}
+
 String GetBuildDateAndTime(void)
 {
   // "2017-03-07T11:08:02" - ISO8601:2004
@@ -356,6 +362,7 @@ void RtcSecond(void)
     ntp_time = sntp_get_current_timestamp();
     if (ntp_time > 1451602800) {  // Fix NTP bug in core 2.4.1/SDK 2.2.1 (returns Thu Jan 01 08:00:10 1970 after power on)
       ntp_force_sync = false;
+      if (utc_time > 1451602800) { drift_time = ntp_time - utc_time; }
       utc_time = ntp_time;
       ntp_sync_minute = 60;  // Sync so block further requests
       if (restart_time == 0) {