Add support for Bootmagic lite when using SPLIT_HAND_PIN (#8347)

* Add support for Bootmagic lite when using SPLIT_HAND_PIN

* Deduplicate bootmagic_lite logic from within via

* Revert location of defaults so that user overrides still work for now

* Tidy up code slightly

2 files changed, 53 insertions, 0 deletions

diff --git a/tmk_core/common.mk b/tmk_core/common.mk
index b766ebe97..3cc72a845 100644
--- a/tmk_core/common.mk
+++ b/tmk_core/common.mk
@@ -34,6 +34,8 @@ ifneq ($(strip $(BOOTMAGIC_ENABLE)), no)
   endif
   ifeq ($(strip $(BOOTMAGIC_ENABLE)), lite)
       TMK_COMMON_DEFS += -DBOOTMAGIC_LITE
+      TMK_COMMON_SRC += $(COMMON_DIR)/bootmagic_lite.c
+
       TMK_COMMON_DEFS += -DMAGIC_ENABLE
       TMK_COMMON_SRC += $(COMMON_DIR)/magic.c
   else
diff --git a/tmk_core/common/bootmagic_lite.c b/tmk_core/common/bootmagic_lite.c
new file mode 100644
index 000000000..53bd7b1c7
--- /dev/null
+++ b/tmk_core/common/bootmagic_lite.c
@@ -0,0 +1,51 @@
+#include "quantum.h"
+
+bool is_keyboard_left(void);
+
+/** \brief Reset eeprom
+ * 
+ * ...just incase someone wants to only change the eeprom behaviour
+ */
+__attribute__((weak)) void bootmagic_lite_reset_eeprom(void) {
+#if defined(VIA_ENABLE)
+    via_eeprom_reset();
+#else
+    eeconfig_disable();
+#endif
+}
+
+/** \brief The lite version of TMK's bootmagic based on Wilba.
+ *
+ *  100% less potential for accidentally making the keyboard do stupid things.
+ */
+__attribute__((weak)) void bootmagic_lite(void) {
+    // We need multiple scans because debouncing can't be turned off.
+    matrix_scan();
+#if defined(DEBOUNCE) && DEBOUNCE > 0
+    wait_ms(DEBOUNCE * 2);
+#else
+    wait_ms(30);
+#endif
+    matrix_scan();
+
+    // If the configured key (commonly Esc) is held down on power up,
+    // reset the EEPROM valid state and jump to bootloader.
+    // This isn't very generalized, but we need something that doesn't
+    // rely on user's keymaps in firmware or EEPROM.
+    uint8_t row = BOOTMAGIC_LITE_ROW;
+    uint8_t col = BOOTMAGIC_LITE_COLUMN;
+
+#if defined(SPLIT_KEYBOARD) && defined(BOOTMAGIC_LITE_ROW_RIGHT) && defined(BOOTMAGIC_LITE_COLUMN_RIGHT)
+    if (!is_keyboard_left()) {
+        row = BOOTMAGIC_LITE_ROW_RIGHT;
+        col = BOOTMAGIC_LITE_COLUMN_RIGHT;
+    }
+#endif
+
+    if (matrix_get_row(row) & (1 << col)) {
+        bootmagic_lite_reset_eeprom();
+
+        // Jump to bootloader.
+        bootloader_jump();
+    }
+}
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