1 files changed, 58 insertions, 0 deletions
diff --git a/tmk_core/common/sync_timer.c b/tmk_core/common/sync_timer.c
new file mode 100644
index 0000000000..de24b463b6
--- /dev/null
+++ b/tmk_core/common/sync_timer.c
@@ -0,0 +1,58 @@
+/*
+Copyright (C) 2020 Ryan Caltabiano <https://github.com/XScorpion2>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+If you happen to meet one of the copyright holders in a bar you are obligated
+to buy them one pint of beer.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+#include "sync_timer.h"
+#include "keyboard.h"
+
+#if defined(SPLIT_KEYBOARD) && !defined(DISABLE_SYNC_TIMER)
+volatile int32_t sync_timer_ms;
+
+void sync_timer_init(void) { sync_timer_ms = 0; }
+
+void sync_timer_update(uint32_t time) {
+    if (is_keyboard_master()) return;
+    sync_timer_ms = time - timer_read32();
+}
+
+uint16_t sync_timer_read(void) {
+    if (is_keyboard_master()) return timer_read();
+    return sync_timer_read32();
+}
+
+uint32_t sync_timer_read32(void) {
+    if (is_keyboard_master()) return timer_read32();
+    return sync_timer_ms + timer_read32();
+}
+
+uint16_t sync_timer_elapsed(uint16_t last) {
+    if (is_keyboard_master()) return timer_elapsed(last);
+    return TIMER_DIFF_16(sync_timer_read(), last);
+}
+
+uint32_t sync_timer_elapsed32(uint32_t last) {
+    if (is_keyboard_master()) return timer_elapsed32(last);
+    return TIMER_DIFF_32(sync_timer_read32(), last);
+}
+#endif