unify activity detection in PhoneAPI, turn off BLE API while serial API in use

src/mesh/PhoneAPI.cpp

@@ -1,6 +1,7 @@
 #include "PhoneAPI.h"
 #include "MeshService.h"
 #include "NodeDB.h"
+#include "PowerFSM.h"
 #include <assert.h>
 
 PhoneAPI::PhoneAPI()
@@ -14,11 +15,30 @@ void PhoneAPI::init()
     observe(&service.fromNumChanged);
 }
 
+void PhoneAPI::checkConnectionTimeout()
+{
+    if (isConnected) {
+        bool newConnected = (millis() - lastContactMsec < radioConfig.preferences.phone_timeout_secs);
+        if (!newConnected) {
+            isConnected = false;
+            onConnectionChanged(isConnected);
+        }
+    }
+}
+
 /**
  * Handle a ToRadio protobuf
  */
 void PhoneAPI::handleToRadio(const uint8_t *buf, size_t bufLength)
 {
+    powerFSM.trigger(EVENT_CONTACT_FROM_PHONE); // As long as the phone keeps talking to us, don't let the radio go to sleep
+    lastContactMsec = millis();
+    if (!isConnected) {
+        isConnected = true;
+        onConnectionChanged(isConnected);
+    }
+    // return (lastContactMsec != 0) &&
+
     if (pb_decode_from_bytes(buf, bufLength, ToRadio_fields, &toRadioScratch)) {
         switch (toRadioScratch.which_variant) {
         case ToRadio_packet_tag: {
@@ -227,6 +247,8 @@ void PhoneAPI::handleToRadioPacket(MeshPacket *p) {}
 /// If the mesh service tells us fromNum has changed, tell the phone
 int PhoneAPI::onNotify(uint32_t newValue)
 {
+    checkConnectionTimeout(); // a handy place to check if we've heard from the phone (since the BLE version doesn't call this from idle)
+    
     if (state == STATE_SEND_PACKETS || state == STATE_LEGACY) {
         DEBUG_MSG("Telling client we have new packets %u\n", newValue);
         onNowHasData(newValue);

src/mesh/PhoneAPI.h

@@ -50,6 +50,11 @@ class PhoneAPI
     /// Use to ensure that clients don't get confused about old messages from the radio
     uint32_t config_nonce = 0;
 
+    /** the last msec we heard from the client on the other side of this link */
+    uint32_t lastContactMsec = 0;
+
+    bool isConnected = false;
+
   public:
     PhoneAPI();
 
@@ -85,6 +90,12 @@ class PhoneAPI
     /// Our fromradio packet while it is being assembled
     FromRadio fromRadioScratch;
 
+    /// Hookable to find out when connection changes
+    virtual void onConnectionChanged(bool connected) {}
+
+  /// If we haven't heard from the other side in a while then say not connected
+    void checkConnectionTimeout();
+
     /**
      * Subclasses can use this as a hook to provide custom notifications for their transport (i.e. bluetooth notifies)
      */

src/mesh/StreamAPI.cpp

@@ -9,6 +9,7 @@ void StreamAPI::loop()
 {
     writeStream();
     readStream();
+    checkConnectionTimeout();
 }
 
 /**