[Core] Fix "6kro enable" and clarify naming (#14563)

* Fix USB_6KRO_ENABLE compilation errors

* Add info to docs

* Rename define to be more accurate

* Remove unused rule

* Refixe docs

2 files changed, 15 insertions, 5 deletions

diff --git a/tmk_core/common.mk b/tmk_core/common.mk
index 7f7420059..e44ff2f0a 100644
--- a/tmk_core/common.mk
+++ b/tmk_core/common.mk
@@ -63,8 +63,8 @@ ifeq ($(strip $(NKRO_ENABLE)), yes)
     endif
 endif
 
-ifeq ($(strip $(USB_6KRO_ENABLE)), yes)
-    TMK_COMMON_DEFS += -DUSB_6KRO_ENABLE
+ifeq ($(strip $(RING_BUFFERED_6KRO_REPORT_ENABLE)), yes)
+    TMK_COMMON_DEFS += -DRING_BUFFERED_6KRO_REPORT_ENABLE
 endif
 
 ifeq ($(strip $(SLEEP_LED_ENABLE)), yes)
diff --git a/tmk_core/common/report.c b/tmk_core/common/report.c
index 1bcb6f2ad..2a7fc006c 100644
--- a/tmk_core/common/report.c
+++ b/tmk_core/common/report.c
@@ -21,6 +21,16 @@
 #include "util.h"
 #include <string.h>
 
+#ifdef RING_BUFFERED_6KRO_REPORT_ENABLE
+#    define RO_ADD(a, b) ((a + b) % KEYBOARD_REPORT_KEYS)
+#    define RO_SUB(a, b) ((a - b + KEYBOARD_REPORT_KEYS) % KEYBOARD_REPORT_KEYS)
+#    define RO_INC(a)    RO_ADD(a, 1)
+#    define RO_DEC(a)    RO_SUB(a, 1)
+static int8_t cb_head  = 0;
+static int8_t cb_tail  = 0;
+static int8_t cb_count = 0;
+#endif
+
 /** \brief has_anykey
  *
  * FIXME: Needs doc
@@ -54,7 +64,7 @@ uint8_t get_first_key(report_keyboard_t* keyboard_report) {
         return i << 3 | biton(keyboard_report->nkro.bits[i]);
     }
 #endif
-#ifdef USB_6KRO_ENABLE
+#ifdef RING_BUFFERED_6KRO_REPORT_ENABLE
     uint8_t i = cb_head;
     do {
         if (keyboard_report->keys[i] != 0) {
@@ -99,7 +109,7 @@ bool is_key_pressed(report_keyboard_t* keyboard_report, uint8_t key) {
  * FIXME: Needs doc
  */
 void add_key_byte(report_keyboard_t* keyboard_report, uint8_t code) {
-#ifdef USB_6KRO_ENABLE
+#ifdef RING_BUFFERED_6KRO_REPORT_ENABLE
     int8_t i     = cb_head;
     int8_t empty = -1;
     if (cb_count) {
@@ -166,7 +176,7 @@ void add_key_byte(report_keyboard_t* keyboard_report, uint8_t code) {
  * FIXME: Needs doc
  */
 void del_key_byte(report_keyboard_t* keyboard_report, uint8_t code) {
-#ifdef USB_6KRO_ENABLE
+#ifdef RING_BUFFERED_6KRO_REPORT_ENABLE
     uint8_t i = cb_head;
     if (cb_count) {
         do {