ARM split - Add bootmagic/magic keycodes for setting handedness (#6545)

* Add docs on bootmagic/magic keycodes for setting handedness

* Clang format fixes

* Maintain backwards compatibility

* Maintain backwards compatibility

9 files changed, 80 insertions, 33 deletions

diff --git a/docs/feature_bootmagic.md b/docs/feature_bootmagic.md
index fc37a3302b..ed00d51295 100644
--- a/docs/feature_bootmagic.md
+++ b/docs/feature_bootmagic.md
@@ -34,6 +34,8 @@ Hold down the Bootmagic key (Space by default) and the desired hotkey while plug
 |`X`               |Toggle key matrix debugging                  |
 |`K`               |Toggle keyboard debugging                    |
 |`M`               |Toggle mouse debugging                       |
+|`L`               |Set "Left Hand" for EE_HANDS handedness      |
+|`R`               |Set "Right Hand" for EE_HANDS handedness     |
 |Backspace         |Clear the EEPROM                             |
 |Caps Lock         |Toggle treating Caps Lock as Left Control    |
 |Left Control      |Toggle swapping Caps Lock and Left Control   |
@@ -83,6 +85,8 @@ Hold down the Bootmagic key (Space by default) and the desired hotkey while plug
 |`MAGIC_UNSWAP_LCTL_LGUI`          |         |Unswap Left Control and Left GUI          |
 |`MAGIC_SWAP_RCTL_RGUI`            |         |Swap Right Control and Right GUI          |
 |`MAGIC_UNSWAP_RCTL_RGUI`          |         |Unswap Right Control and Right GUI        |
+|`MAGIC_EE_HANDS_LEFT`             |         |Set "Left Hand" for EE_HANDS handedness   |
+|`MAGIC_EE_HANDS_RIGHT`            |         |Set "Right Hand" for EE_HANDS handedness  |
 
 ## Configuration
 
@@ -98,6 +102,8 @@ If you would like to change the hotkey assignments for Bootmagic, `#define` thes
 |`BOOTMAGIC_KEY_DEBUG_MATRIX`            |`KC_X`       |Toggle matrix debugging                            |
 |`BOOTMAGIC_KEY_DEBUG_KEYBOARD`          |`KC_K`       |Toggle keyboard debugging                          |
 |`BOOTMAGIC_KEY_DEBUG_MOUSE`             |`KC_M`       |Toggle mouse debugging                             |
+|`BOOTMAGIC_KEY_EE_HANDS_LEFT`           |`KC_L`       |Set "Left Hand" for EE_HANDS handedness            |
+|`BOOTMAGIC_KEY_EE_HANDS_RIGHT`          |`KC_R`       |Set "Right Hand" for EE_HANDS handedness           |
 |`BOOTMAGIC_KEY_SWAP_CONTROL_CAPSLOCK`   |`KC_LCTRL`   |Swap Left Control and Caps Lock                    |
 |`BOOTMAGIC_KEY_CAPSLOCK_TO_CONTROL`     |`KC_CAPSLOCK`|Toggle treating Caps Lock as Left Control          |
 |`BOOTMAGIC_KEY_SWAP_LALT_LGUI`          |`KC_LALT`    |Toggle swapping Left Alt and Left GUI (for macOS)  |
diff --git a/docs/keycodes.md b/docs/keycodes.md
index e17fef6fd2..dfbab148b8 100644
--- a/docs/keycodes.md
+++ b/docs/keycodes.md
@@ -257,35 +257,37 @@ This is a reference only. Each group of keys links to the page documenting their
 
 ## [Bootmagic](feature_bootmagic.md)
 
-|Key                               |Aliases  |Description                         |
-|----------------------------------|---------|------------------------------------|
-|`MAGIC_SWAP_CONTROL_CAPSLOCK`     |         |Swap Caps Lock and Left Control     |
-|`MAGIC_CAPSLOCK_TO_CONTROL`       |         |Treat Caps Lock as Control          |
-|`MAGIC_SWAP_LCTL_LGUI`            |         |Swap Left Control and GUI           |
-|`MAGIC_SWAP_RCTL_RGUI`            |         |Swap Right Control and GUI          |
-|`MAGIC_SWAP_LALT_LGUI`            |         |Swap Left Alt and GUI               |
-|`MAGIC_SWAP_RALT_RGUI`            |         |Swap Right Alt and GUI              |
-|`MAGIC_NO_GUI`                    |         |Disable the GUI key                 |
-|`MAGIC_SWAP_GRAVE_ESC`            |         |Swap <code>&#96;</code> and Escape  |
-|`MAGIC_SWAP_BACKSLASH_BACKSPACE`  |         |Swap `\` and Backspace              |
-|`MAGIC_HOST_NKRO`                 |         |Force NKRO on                       |
-|`MAGIC_SWAP_ALT_GUI`              |`AG_SWAP`|Swap Alt and GUI on both sides      |
+|Key                               |Aliases  |Description                                |
+|----------------------------------|---------|-------------------------------------------|
+|`MAGIC_SWAP_CONTROL_CAPSLOCK`     |         |Swap Caps Lock and Left Control            |
+|`MAGIC_CAPSLOCK_TO_CONTROL`       |         |Treat Caps Lock as Control                 |
+|`MAGIC_SWAP_LCTL_LGUI`            |         |Swap Left Control and GUI                  |
+|`MAGIC_SWAP_RCTL_RGUI`            |         |Swap Right Control and GUI                 |
+|`MAGIC_SWAP_LALT_LGUI`            |         |Swap Left Alt and GUI                      |
+|`MAGIC_SWAP_RALT_RGUI`            |         |Swap Right Alt and GUI                     |
+|`MAGIC_NO_GUI`                    |         |Disable the GUI key                        |
+|`MAGIC_SWAP_GRAVE_ESC`            |         |Swap <code>&#96;</code> and Escape         |
+|`MAGIC_SWAP_BACKSLASH_BACKSPACE`  |         |Swap `\` and Backspace                     |
+|`MAGIC_HOST_NKRO`                 |         |Force NKRO on                              |
+|`MAGIC_SWAP_ALT_GUI`              |`AG_SWAP`|Swap Alt and GUI on both sides             |
 |`MAGIC_SWAP_CTL_GUI`              |`CG_SWAP`|Swap Ctrl and GUI on both sides (for macOS)|
-|`MAGIC_UNSWAP_CONTROL_CAPSLOCK`   |         |Unswap Caps Lock and Left Control   |
-|`MAGIC_UNCAPSLOCK_TO_CONTROL`     |         |Stop treating Caps Lock as Control  |
-|`MAGIC_UNSWAP_LCTL_LGUI`          |         |Unswap Left Control and GUI         |
-|`MAGIC_UNSWAP_RCTL_RGUI`          |         |Unswap Right Control and GUI        |
-|`MAGIC_UNSWAP_LALT_LGUI`          |         |Unswap Left Alt and GUI             |
-|`MAGIC_UNSWAP_RALT_RGUI`          |         |Unswap Right Alt and GUI            |
-|`MAGIC_UNNO_GUI`                  |         |Enable the GUI key                  |
-|`MAGIC_UNSWAP_GRAVE_ESC`          |         |Unswap <code>&#96;</code> and Escape|
-|`MAGIC_UNSWAP_BACKSLASH_BACKSPACE`|         |Unswap `\` and Backspace            |
-|`MAGIC_UNHOST_NKRO`               |         |Force NKRO off                      |
-|`MAGIC_UNSWAP_ALT_GUI`            |`AG_NORM`|Unswap Alt and GUI on both sides    |
-|`MAGIC_UNSWAP_CTL_GUI`            |`CG_NORM`|Unswap Ctrl and GUI on both sides      |
-|`MAGIC_TOGGLE_ALT_GUI`            |`AG_TOGG`|Toggle Alt and GUI swap on both sides  |
-|`MAGIC_TOGGLE_CTL_GUI`            |`CG_TOGG`|Toggle Ctrl and GUI swap on both sides |
-|`MAGIC_TOGGLE_NKRO`               |         |Turn NKRO on or off                    |
+|`MAGIC_UNSWAP_CONTROL_CAPSLOCK`   |         |Unswap Caps Lock and Left Control          |
+|`MAGIC_UNCAPSLOCK_TO_CONTROL`     |         |Stop treating Caps Lock as Control         |
+|`MAGIC_UNSWAP_LCTL_LGUI`          |         |Unswap Left Control and GUI                |
+|`MAGIC_UNSWAP_RCTL_RGUI`          |         |Unswap Right Control and GUI               |
+|`MAGIC_UNSWAP_LALT_LGUI`          |         |Unswap Left Alt and GUI                    |
+|`MAGIC_UNSWAP_RALT_RGUI`          |         |Unswap Right Alt and GUI                   |
+|`MAGIC_UNNO_GUI`                  |         |Enable the GUI key                         |
+|`MAGIC_UNSWAP_GRAVE_ESC`          |         |Unswap <code>&#96;</code> and Escape       |
+|`MAGIC_UNSWAP_BACKSLASH_BACKSPACE`|         |Unswap `\` and Backspace                   |
+|`MAGIC_UNHOST_NKRO`               |         |Force NKRO off                             |
+|`MAGIC_UNSWAP_ALT_GUI`            |`AG_NORM`|Unswap Alt and GUI on both sides           |
+|`MAGIC_UNSWAP_CTL_GUI`            |`CG_NORM`|Unswap Ctrl and GUI on both sides          |
+|`MAGIC_TOGGLE_ALT_GUI`            |`AG_TOGG`|Toggle Alt and GUI swap on both sides      |
+|`MAGIC_TOGGLE_CTL_GUI`            |`CG_TOGG`|Toggle Ctrl and GUI swap on both sides     |
+|`MAGIC_TOGGLE_NKRO`               |         |Turn NKRO on or off                        |
+|`MAGIC_EE_HANDS_LEFT`             |         |Set "Left Hand" for EE_HANDS handedness    |
+|`MAGIC_EE_HANDS_RIGHT`            |         |Set "Right Hand" for EE_HANDS handedness   |
 
 ## [Bluetooth](feature_bluetooth.md)
 
diff --git a/quantum/quantum.c b/quantum/quantum.c
index ec80fa557f..16922dd011 100644
--- a/quantum/quantum.c
+++ b/quantum/quantum.c
@@ -544,7 +544,7 @@ bool process_record_quantum(keyrecord_t *record) {
 #    endif
 #endif
         case MAGIC_SWAP_CONTROL_CAPSLOCK ... MAGIC_TOGGLE_ALT_GUI:
-        case MAGIC_SWAP_LCTL_LGUI ... MAGIC_TOGGLE_CTL_GUI:
+        case MAGIC_SWAP_LCTL_LGUI ... MAGIC_EE_HANDS_RIGHT:
             if (record->event.pressed) {
                 // MAGIC actions (BOOTMAGIC without the boot)
                 if (!eeconfig_is_enabled()) {
@@ -662,6 +662,12 @@ bool process_record_quantum(keyrecord_t *record) {
                     case MAGIC_TOGGLE_NKRO:
                         keymap_config.nkro = !keymap_config.nkro;
                         break;
+                    case MAGIC_EE_HANDS_LEFT:
+                        eeconfig_update_handedness(true);
+                        break;
+                    case MAGIC_EE_HANDS_RIGHT:
+                        eeconfig_update_handedness(false);
+                        break;
                     default:
                         break;
                 }
diff --git a/quantum/quantum_keycodes.h b/quantum/quantum_keycodes.h
index af984a7cd7..5fac6a5cae 100644
--- a/quantum/quantum_keycodes.h
+++ b/quantum/quantum_keycodes.h
@@ -502,6 +502,8 @@ enum quantum_keycodes {
     MAGIC_SWAP_CTL_GUI,
     MAGIC_UNSWAP_CTL_GUI,
     MAGIC_TOGGLE_CTL_GUI,
+    MAGIC_EE_HANDS_LEFT,
+    MAGIC_EE_HANDS_RIGHT,
 
     // always leave at the end
     SAFE_RANGE
diff --git a/quantum/split_common/split_util.c b/quantum/split_common/split_util.c
index 5114b188ec..d16a989770 100644
--- a/quantum/split_common/split_util.c
+++ b/quantum/split_common/split_util.c
@@ -7,7 +7,6 @@
 #include "quantum.h"
 
 #ifdef EE_HANDS
-#    include "tmk_core/common/eeprom.h"
 #    include "eeconfig.h"
 #endif
 
@@ -23,7 +22,7 @@ __attribute__((weak)) bool is_keyboard_left(void) {
     setPinInput(SPLIT_HAND_PIN);
     return readPin(SPLIT_HAND_PIN);
 #elif defined(EE_HANDS)
-    return eeprom_read_byte(EECONFIG_HANDEDNESS);
+    return eeconfig_read_handedness();
 #elif defined(MASTER_RIGHT)
     return !is_keyboard_master();
 #endif
diff --git a/tmk_core/common/bootmagic.c b/tmk_core/common/bootmagic.c
index 09b1664c90..bb2aa0db8c 100644
--- a/tmk_core/common/bootmagic.c
+++ b/tmk_core/common/bootmagic.c
@@ -122,6 +122,14 @@ void bootmagic(void) {
         default_layer = eeconfig_read_default_layer();
         default_layer_set((layer_state_t)default_layer);
     }
+
+    /* EE_HANDS handedness */
+    if (bootmagic_scan_keycode(BOOTMAGIC_KEY_EE_HANDS_LEFT)) {
+        eeconfig_update_handedness(true);
+    }
+    if (bootmagic_scan_keycode(BOOTMAGIC_KEY_EE_HANDS_RIGHT)) {
+        eeconfig_update_handedness(false);
+    }
 }
 
 /** \brief Scan Keycode
diff --git a/tmk_core/common/bootmagic.h b/tmk_core/common/bootmagic.h
index fb76472579..c64dc17858 100644
--- a/tmk_core/common/bootmagic.h
+++ b/tmk_core/common/bootmagic.h
@@ -36,6 +36,12 @@
 #ifndef BOOTMAGIC_KEY_DEBUG_MOUSE
 #    define BOOTMAGIC_KEY_DEBUG_MOUSE KC_M
 #endif
+#ifndef BOOTMAGIC_KEY_EE_HANDS_LEFT
+#    define BOOTMAGIC_KEY_EE_HANDS_LEFT KC_L
+#endif
+#ifndef BOOTMAGIC_KEY_EE_HANDS_RIGHT
+#    define BOOTMAGIC_KEY_EE_HANDS_RIGHT KC_R
+#endif
 
 /*
  * keymap config
diff --git a/tmk_core/common/eeconfig.c b/tmk_core/common/eeconfig.c
index 61aaec2054..933ac42bd2 100644
--- a/tmk_core/common/eeconfig.c
+++ b/tmk_core/common/eeconfig.c
@@ -153,8 +153,8 @@ uint32_t eeconfig_read_kb(void) { return eeprom_read_dword(EECONFIG_KEYBOARD); }
  *
  * FIXME: needs doc
  */
-
 void eeconfig_update_kb(uint32_t val) { eeprom_update_dword(EECONFIG_KEYBOARD, val); }
+
 /** \brief eeconfig read user
  *
  * FIXME: needs doc
@@ -166,9 +166,24 @@ uint32_t eeconfig_read_user(void) { return eeprom_read_dword(EECONFIG_USER); }
  */
 void eeconfig_update_user(uint32_t val) { eeprom_update_dword(EECONFIG_USER, val); }
 
+/** \brief eeconfig read haptic
+ *
+ * FIXME: needs doc
+ */
 uint32_t eeconfig_read_haptic(void) { return eeprom_read_dword(EECONFIG_HAPTIC); }
-/** \brief eeconfig update user
+/** \brief eeconfig update haptic
  *
  * FIXME: needs doc
  */
 void eeconfig_update_haptic(uint32_t val) { eeprom_update_dword(EECONFIG_HAPTIC, val); }
+
+/** \brief eeconfig read split handedness
+ *
+ * FIXME: needs doc
+ */
+bool eeconfig_read_handedness(void) { return !!eeprom_read_byte(EECONFIG_HANDEDNESS); }
+/** \brief eeconfig update split handedness
+ *
+ * FIXME: needs doc
+ */
+void eeconfig_update_handedness(bool val) { eeprom_update_byte(EECONFIG_HANDEDNESS, !!val); }
diff --git a/tmk_core/common/eeconfig.h b/tmk_core/common/eeconfig.h
index aea4eff9f6..308f865e19 100644
--- a/tmk_core/common/eeconfig.h
+++ b/tmk_core/common/eeconfig.h
@@ -107,4 +107,7 @@ uint32_t eeconfig_read_haptic(void);
 void     eeconfig_update_haptic(uint32_t val);
 #endif
 
+bool eeconfig_read_handedness(void);
+void eeconfig_update_handedness(bool val);
+
 #endif