WIP add support for i2C GPS

src/gps/GPS.cpp

@@ -5,6 +5,7 @@
 #include <assert.h>
 #include <time.h>
 
+// If we have a serial GPS port it will not be null
 #ifdef GPS_RX_PIN
 HardwareSerial _serial_gps_real(GPS_SERIAL_NUM);
 HardwareSerial *GPS::_serial_gps = &_serial_gps_real;
@@ -15,6 +16,8 @@ HardwareSerial *GPS::_serial_gps = &Serial1;
 HardwareSerial *GPS::_serial_gps = NULL;
 #endif
 
+uint8_t GPS::i2cAddress = 0;
+
 bool timeSetFromGPS; // We try to set our time from GPS each time we wake from sleep
 
 GPS *gps;

src/gps/GPS.h

@@ -1,8 +1,8 @@
 #pragma once
 
-#include "Observer.h"
-#include "GPSStatus.h"
 #include "../concurrency/PeriodicTask.h"
+#include "GPSStatus.h"
+#include "Observer.h"
 #include "sys/time.h"
 
 /// If we haven't yet set our RTC this boot, set it from a GPS derived time
@@ -30,12 +30,17 @@ class GPS : public Observable<void *>
   protected:
     bool hasValidLocation = false; // default to false, until we complete our first read
 
+  public:
+    /** If !NULL we will use this serial port to construct our GPS */
     static HardwareSerial *_serial_gps;
 
-  public:
+    /** If !0 we will attempt to connect to the GPS over I2C */
+    static uint8_t i2cAddress;
+
     int32_t latitude = 0, longitude = 0; // as an int mult by 1e-7 to get value as double
     int32_t altitude = 0;
-    uint32_t dop = 0; // Diminution of position; PDOP where possible (UBlox), HDOP otherwise (TinyGPS) in 10^2 units (needs scaling before use)
+    uint32_t dop = 0;     // Diminution of position; PDOP where possible (UBlox), HDOP otherwise (TinyGPS) in 10^2 units (needs
+                          // scaling before use)
     uint32_t heading = 0; // Heading of motion, in degrees * 10^-5
     uint32_t numSatellites = 0;
 

src/gps/UBloxGPS.cpp

@@ -7,23 +7,35 @@ UBloxGPS::UBloxGPS() : concurrency::PeriodicTask()
     notifySleepObserver.observe(&notifySleep);
 }
 
+bool UBloxGPS::tryConnect()
+{
+    isConnected = false;
+
+    if (_serial_gps)
+        isConnected = ublox.begin(*_serial_gps);
+
+    if (!isConnected && i2cAddress)
+        isConnected = ublox.begin(Wire, i2cAddress);
+
+    return isConnected;
+}
+
 bool UBloxGPS::setup()
 {
+    if (_serial_gps) {
 #ifdef GPS_RX_PIN
-    _serial_gps->begin(GPS_BAUDRATE, SERIAL_8N1, GPS_RX_PIN, GPS_TX_PIN);
+        _serial_gps->begin(GPS_BAUDRATE, SERIAL_8N1, GPS_RX_PIN, GPS_TX_PIN);
 #else
-    _serial_gps->begin(GPS_BAUDRATE);
+        _serial_gps->begin(GPS_BAUDRATE);
 #endif
-    // _serial_gps.setRxBufferSize(1024); // the default is 256
+        // _serial_gps.setRxBufferSize(1024); // the default is 256
+    }
+
     // ublox.enableDebugging(Serial);
 
-    // note: the lib's implementation has the wrong docs for what the return val is
-    // it is not a bool, it returns zero for success
-    isConnected = ublox.begin(*_serial_gps);
-
     // try a second time, the ublox lib serial parsing is buggy?
-    if (!isConnected)
-        isConnected = ublox.begin(*_serial_gps);
+    if (!tryConnect())
+        tryConnect();
 
     if (isConnected) {
         DEBUG_MSG("Connected to UBLOX GPS successfully\n");
@@ -35,7 +47,7 @@ bool UBloxGPS::setup()
             // GPS_TX connected)
             ublox.factoryReset();
             delay(3000);
-            isConnected = ublox.begin(*_serial_gps);
+            tryConnect();
             DEBUG_MSG("Factory reset success=%d\n", isConnected);
             ok = ublox.saveConfiguration(3000);
             assert(ok);
@@ -131,7 +143,8 @@ The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of s
         wantNewLocation = true;
 
     // Notify any status instances that are observing us
-    const meshtastic::GPSStatus status = meshtastic::GPSStatus(hasLock(), isConnected, latitude, longitude, altitude, dop, heading, numSatellites);
+    const meshtastic::GPSStatus status =
+        meshtastic::GPSStatus(hasLock(), isConnected, latitude, longitude, altitude, dop, heading, numSatellites);
     newStatus.notifyObservers(&status);
 
     // Once we have sent a location once we only poll the GPS rarely, otherwise check back every 1s until we have something over

src/gps/UBloxGPS.h

@@ -38,4 +38,7 @@ class UBloxGPS : public GPS, public concurrency::PeriodicTask
     /// Prepare the GPS for the cpu entering deep or light sleep, expect to be gone for at least 100s of msecs
     /// always returns 0 to indicate okay to sleep
     int prepareSleep(void *unused);
+
+    /// Attempt to connect to our GPS, returns false if no gps is present
+    bool tryConnect();
 };

src/main.cpp

@@ -269,8 +269,12 @@ void setup()
         // assume NEMA at 9600 baud.
         DEBUG_MSG("ERROR: No UBLOX GPS found, hoping that NEMA might work\n");
         delete gps;
-        gps = new NEMAGPS();
-        gps->setup();
+
+        if(GPS::_serial_gps) {
+            // dumb NEMA access only work for serial GPSes)
+            gps = new NEMAGPS();
+            gps->setup();
+        }
     }
 #else
     gps = new NEMAGPS();