From d60d1d74477a5ad3f5d6785b8157f255bb0bbfd4 Mon Sep 17 00:00:00 2001
From: todd-herbert <herbert.todd@gmail.com>
Date: Wed, 12 Jun 2024 23:34:00 +1200
Subject: [PATCH] Workaround to disable bluetooth on NRF52 (#4055)

* Workaround to allow bluetooth disable on NRF52

* Use miminum tx power for bluetooth

* Reorganize

* Instantiate nrf52Bluetooth correctly..

* Change log message
---
 src/platform/nrf52/NRF52Bluetooth.cpp | 12 ++++++
 src/platform/nrf52/NRF52Bluetooth.h   |  1 +
 src/platform/nrf52/main-nrf52.cpp     | 55 ++++++++++++++++++---------
 3 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/src/platform/nrf52/NRF52Bluetooth.cpp b/src/platform/nrf52/NRF52Bluetooth.cpp
index 39898ab25..4c25f38ea 100644
--- a/src/platform/nrf52/NRF52Bluetooth.cpp
+++ b/src/platform/nrf52/NRF52Bluetooth.cpp
@@ -215,6 +215,18 @@ void NRF52Bluetooth::shutdown()
     Bluefruit.Advertising.stop();
 }
 
+void NRF52Bluetooth::startDisabled()
+{
+    // Setup Bluetooth
+    nrf52Bluetooth->setup();
+
+    // Shutdown bluetooth for minimum power draw
+    Bluefruit.Advertising.stop();
+    Bluefruit.setTxPower(-40); // Minimum power
+
+    LOG_INFO("Disabling NRF52 Bluetooth. (Workaround: tx power min, advertising stopped)\n");
+}
+
 bool NRF52Bluetooth::isConnected()
 {
     return Bluefruit.connected(connectionHandle);
diff --git a/src/platform/nrf52/NRF52Bluetooth.h b/src/platform/nrf52/NRF52Bluetooth.h
index 11e18c127..450af47f9 100644
--- a/src/platform/nrf52/NRF52Bluetooth.h
+++ b/src/platform/nrf52/NRF52Bluetooth.h
@@ -8,6 +8,7 @@ class NRF52Bluetooth : BluetoothApi
   public:
     void setup();
     void shutdown();
+    void startDisabled();
     void resumeAdvertising();
     void clearBonds();
     bool isConnected();
diff --git a/src/platform/nrf52/main-nrf52.cpp b/src/platform/nrf52/main-nrf52.cpp
index 9cc52a7de..1f2c6867d 100644
--- a/src/platform/nrf52/main-nrf52.cpp
+++ b/src/platform/nrf52/main-nrf52.cpp
@@ -68,28 +68,47 @@ static const bool useSoftDevice = true; // Set to false for easier debugging
 #if !MESHTASTIC_EXCLUDE_BLUETOOTH
 void setBluetoothEnable(bool enable)
 {
-    if (enable && config.bluetooth.enabled) {
-        if (!useSoftDevice) {
+    // For debugging use: don't use bluetooth
+    if (!useSoftDevice) {
+        if (enable)
             LOG_INFO("DISABLING NRF52 BLUETOOTH WHILE DEBUGGING\n");
-        } else {
-            if (!nrf52Bluetooth) {
-                LOG_DEBUG("Initializing NRF52 Bluetooth\n");
-                nrf52Bluetooth = new NRF52Bluetooth();
-                nrf52Bluetooth->setup();
-
-                // We delay brownout init until after BLE because BLE starts soft device
-                initBrownout();
-            } else {
-                nrf52Bluetooth->resumeAdvertising();
-            }
-        }
-    } else {
-        if (nrf52Bluetooth) {
-            nrf52Bluetooth->shutdown();
-        }
+        return;
     }
+
+    // If user disabled bluetooth: init then disable advertising & reduce power
+    // Workaround. Avoid issue where device hangs several days after boot..
+    // Allegedly, no significant increase in power consumption
+    if (!config.bluetooth.enabled) {
+        static bool initialized = false;
+        if (!initialized) {
+            nrf52Bluetooth = new NRF52Bluetooth();
+            nrf52Bluetooth->startDisabled();
+            initBrownout();
+            initialized = true;
+        }
+        return;
+    }
+
+    if (enable) {
+        // If not yet set-up
+        if (!nrf52Bluetooth) {
+            LOG_DEBUG("Initializing NRF52 Bluetooth\n");
+            nrf52Bluetooth = new NRF52Bluetooth();
+            nrf52Bluetooth->setup();
+
+            // We delay brownout init until after BLE because BLE starts soft device
+            initBrownout();
+        }
+        // Already setup, apparently
+        else
+            nrf52Bluetooth->resumeAdvertising();
+    }
+    // Disable (if previously set-up)
+    else if (nrf52Bluetooth)
+        nrf52Bluetooth->shutdown();
 }
 #else
+#warning NRF52 "Bluetooth disable" workaround does not apply to builds with MESHTASTIC_EXCLUDE_BLUETOOTH
 void setBluetoothEnable(bool enable) {}
 #endif
 /**