Add saved LED controls across supported boards

Add get leds and set leds on|off for Companion, repeater, room server and
sensor builds. Preserve the setting across reboots and cover GPIO, RGB,
Bluetooth, notification and expander indicators without changing radio
amplifier controls or screen backlights.

RAK Companions blink while advertising and keep the Bluetooth LED off once
connected, including late timer callbacks.

Adapted from meshcore-dev/MeshCore#3605 and #2694.
Validated with host regressions and firmware builds for SenseCAP Solar,
RAK4631, T096, Heltec V4, T-Beam, Xiao S3, Pico W and Wio E5 Mini.

Co-authored-by: R0ck <develop@hectospark.co.uk>
Co-authored-by: Nick Dunklee <nick@dunklee.org>

scripts/nrf52_ble_cccd_fix.py

@@ -155,6 +155,49 @@ def patched_trace_source(source):
 ''')
 
 
+def patched_led_source(source):
+    """A queued advertising blink must not relight a disabled indicator."""
+    source = source.replace("\r\n", "\n")
+    old = """  (void) xTimer;
+  digitalToggle(LED_BLUE);
+"""
+    new = """  (void) xTimer;
+  // MeshCore saved LED policy also covers already queued timer callbacks.
+  if (LED_BLUE < 0 || (uint32_t)LED_BLUE >= PINS_COUNT) return;
+  if (digitalPinToPinName(LED_BLUE) == 0xff) return;
+#ifdef DISABLE_BLE_LED
+  const bool enabled = false;
+#elif defined(RAK_BOARD) && defined(BLE_PIN_CODE)
+  const bool enabled = mesh::leds::enabled() && !Bluefruit.connected();
+#else
+  const bool enabled = mesh::leds::enabled();
+#endif
+  if (enabled) digitalToggle(LED_BLUE);
+  else digitalWrite(LED_BLUE, !LED_STATE_ON);
+"""
+    include = '#include "bluefruit.h"\n'
+    policy_include = '#include <helpers/LedPolicy.h>\n'
+    old_connected = "    digitalWrite(LED_BLUE, on_off ? LED_STATE_ON : (1-LED_STATE_ON) );"
+    new_connected = """    // RAK Companions blink while advertising, then go dark when connected.
+#if defined(DISABLE_BLE_LED) || (defined(RAK_BOARD) && defined(BLE_PIN_CODE))
+    on_off = false;
+#else
+    on_off = on_off && mesh::leds::enabled();
+#endif
+    if (LED_BLUE >= 0 && (uint32_t)LED_BLUE < PINS_COUNT
+        && digitalPinToPinName(LED_BLUE) != 0xff)
+      digitalWrite(LED_BLUE, on_off ? LED_STATE_ON : (1-LED_STATE_ON));"""
+    if (new in source and new_connected in source
+            and policy_include in source and old not in source
+            and old_connected not in source):
+        return source
+    if (source.count(old) != 1 or source.count(include) != 1
+            or source.count(old_connected) != 1):
+        raise RuntimeError("nRF52 BLE LED policy: unrecognized timer callback")
+    return source.replace(old, new).replace(old_connected, new_connected).replace(
+        include, include + policy_include)
+
+
 def replace_framework_source(build_env, node):
     source = Path(node.srcnode().get_abspath())
     if source.name not in ("BLEGatt.cpp", "BLEConnection.cpp", "bluefruit.cpp") or source.parent.name != "src":
@@ -166,6 +209,8 @@ def replace_framework_source(build_env, node):
         patched = patched_connection_source(original)
     else:
         patched = patched_bluefruit_source(original)
+        patched = patched_led_source(patched)
+        build_env.AppendUnique(CPPPATH=[build_env.subst("$PROJECT_DIR/src")])
         if "MESH_NRF52_BLE_TRACE" in str(build_env.get("CPPDEFINES", [])):
             patched = patched_trace_source(patched)
             build_env.AppendUnique(CPPPATH=[build_env.subst("$PROJECT_DIR/src")])