change USBQuirks LEDs to B, N

Also, add a method to override the indicators, and document.

plugins/Kaleidoscope-USB-Quirks/README.md

@@ -35,6 +35,10 @@ The plugin provides one object, `USBQuirks`, which provides the following method
 > to detach and then re-attach to the host. (This re-attach is necessary to
 > force re-enumeration with a different Report Descriptor.)
 >
+> Switching the toggle also lights up a key indicating the mode being
+> switched to: by default, `B` for boot reports only, and `N` for extended
+> reports enabled.
+>
 > The extended key report supports n-key rollover (NKRO), and is actually a
 > hybrid, having a prefix containing the boot report, for compatibility
 > with older hosts. The boot report only supports 6-key rollover (6KRO),
@@ -49,3 +53,8 @@ The plugin provides one object, `USBQuirks`, which provides the following method
 > of the hybrid extended report should accommodate some of these hosts.
 > This toggle helps to work with hosts that neither request boot protocol
 > nor tolerate the longer hybrid report.
+
+### `.setKeys(Key boot_led, Key nkro_led)`
+
+> Set which keys to light up to indicate the target mode. Defaults to
+> `(Key_B, Key_N)`.

plugins/Kaleidoscope-USB-Quirks/src/kaleidoscope/plugin/USB-Quirks.cpp

@@ -29,7 +29,10 @@
 namespace kaleidoscope {
 namespace plugin {
 
-KeyAddr findKey(Key search_key) {
+KeyAddr USBQuirks::key_boot_addr = KeyAddr::none();
+KeyAddr USBQuirks::key_nkro_addr = KeyAddr::none();
+
+static KeyAddr findKey(Key search_key) {
   for (auto key_addr : KeyAddr::all()) {
     Key k = Layer.lookupOnActiveLayer(key_addr);
 
@@ -40,9 +43,13 @@ KeyAddr findKey(Key search_key) {
   return KeyAddr::none();
 }
 
+void USBQuirks::setKeys(Key boot_led, Key nkro_led) {
+  key_boot_addr = findKey(boot_led);
+  key_nkro_addr = findKey(nkro_led);
+}
+
 EventHandlerResult USBQuirks::onSetup() {
-  key_6_addr = findKey(Key_6);
-  key_n_addr = findKey(Key_N);
+  setKeys(Key_B, Key_N);
   return EventHandlerResult::OK;
 }
 
@@ -51,9 +58,9 @@ void USBQuirks::toggleKeyboardProtocol() {
   uint8_t new_bootonly = !Runtime.hid().keyboard().getBootOnly();
 
   if (new_bootonly) {
-    key_addr = key_6_addr;
+    key_addr = key_boot_addr;
   } else {
-    key_addr = key_n_addr;
+    key_addr = key_nkro_addr;
   }
   ::LEDControl.disable();
   if (key_addr.isValid()) {

plugins/Kaleidoscope-USB-Quirks/src/kaleidoscope/plugin/USB-Quirks.h

@@ -19,6 +19,7 @@
 
 #include "kaleidoscope/KeyAddr.h"               // for KeyAddr
 #include "kaleidoscope/event_handler_result.h"  // for EventHandlerResult
+#include "kaleidoscope/key_defs.h"              // for Key
 #include "kaleidoscope/plugin.h"                // for Plugin
 
 namespace kaleidoscope {
@@ -27,10 +28,11 @@ class USBQuirks : public kaleidoscope::Plugin {
  public:
   void toggleKeyboardProtocol();
   EventHandlerResult onSetup();
+  static void setKeys(Key boot_led, Key nkro_led);
 
  private:
-  KeyAddr key_6_addr;
-  KeyAddr key_n_addr;
+  static KeyAddr key_boot_addr;
+  static KeyAddr key_nkro_addr;
 };
 
 }  // namespace plugin