coroutine: kinda works now

src/gps/GPS.cpp

@@ -143,7 +143,7 @@ void GPS::publishUpdate()
     }
 }
 
-void GPS::loop()
+int32_t GPS::runOnce()
 {
     if (whileIdle()) {
         // if we have received valid NMEA claim we are connected
@@ -201,6 +201,10 @@ void GPS::loop()
 
     // If state has changed do a publish
     publishUpdate();
+
+    // 9600bps is approx 1 byte per msec, so considering our buffer size we never need to wake more often than 200ms
+    // if not awake we can run super infrquently (once every 5 secs?) to see if we need to wake.
+    return isAwake ? 100 : 5000;
 }
 
 void GPS::forceWake(bool on)

src/gps/GPS.h

@@ -2,6 +2,7 @@
 
 #include "GPSStatus.h"
 #include "Observer.h"
+#include "concurrency/OSThread.h"
 
 // Generate a string representation of DOP
 const char *getDOPString(uint32_t dop);
@@ -11,7 +12,7 @@ const char *getDOPString(uint32_t dop);
  *
  * When new data is available it will notify observers.
  */
-class GPS
+class GPS : private concurrency::OSThread
 {
   private:
     uint32_t lastWakeStartMsec = 0, lastSleepStartMsec = 0, lastWhileActiveMsec = 0;
@@ -43,6 +44,8 @@ class GPS
                           // scaling before use)
     uint32_t heading = 0; // Heading of motion, in degrees * 10^-5
 
+    GPS() : concurrency::OSThread("GPS") {}
+
     virtual ~GPS() {} // FIXME, we really should unregister our sleep observer
 
     /** We will notify this observable anytime GPS state has changed meaningfully */
@@ -53,8 +56,6 @@ class GPS
      */
     virtual bool setup();
 
-    virtual void loop();
-
     /// Returns ture if we have acquired GPS lock.
     bool hasLock() const { return hasValidLocation; }
 
@@ -135,6 +136,8 @@ class GPS
      * Tell users we have new GPS readings
      */
     void publishUpdate();
+
+    virtual int32_t runOnce();
 };
 
 extern GPS *gps;