[Core] Tri Layer Keys (#19795)

Co-authored-by: wilba <wilba@wilba.tech>
Co-authored-by: Pablo Martínez <58857054+elpekenin@users.noreply.github.com>
Co-authored-by: Joel Challis <git@zvecr.com>
Co-authored-by: Nick Brassel <nick@tzarc.org>

1 files changed, 59 insertions, 0 deletions

diff --git a/quantum/tri_layer.h b/quantum/tri_layer.h
new file mode 100644
index 0000000000..3341ebffb2
--- /dev/null
+++ b/quantum/tri_layer.h
@@ -0,0 +1,59 @@
+// Copyright 2023 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <stdint.h>
+
+#ifndef TRI_LAYER_LOWER_LAYER
+#    define TRI_LAYER_LOWER_LAYER 1
+#endif
+#ifndef TRI_LAYER_UPPER_LAYER
+#    define TRI_LAYER_UPPER_LAYER 2
+#endif
+#ifndef TRI_LAYER_ADJUST_LAYER
+#    define TRI_LAYER_ADJUST_LAYER 3
+#endif
+
+/**
+ * @brief Set the tri layer lower layer index
+ *
+ * @param layer
+ */
+void set_tri_layer_lower_layer(uint8_t layer);
+/**
+ * @brief Set the tri layer upper layer index
+ *
+ * @param layer
+ */
+void set_tri_layer_upper_layer(uint8_t layer);
+/**
+ * @brief Set the tri layer adjust layer index
+ *
+ * @param layer
+ */
+void set_tri_layer_adjust_layer(uint8_t layer);
+/**
+ * @brief Set the tri layer indices
+ *
+ * @param lower
+ * @param upper
+ * @param adjust
+ */
+void set_tri_layer_layers(uint8_t lower, uint8_t upper, uint8_t adjust);
+/**
+ * @brief Get the tri layer lower layer index
+ *
+ * @return uint8_t
+ */
+uint8_t get_tri_layer_lower_layer(void);
+/**
+ * @brief Get the tri layer upper layer index
+ *
+ * @return uint8_t
+ */
+uint8_t get_tri_layer_upper_layer(void);
+/**
+ * @brief Get the tri layer adjust layer index
+ *
+ * @return uint8_t
+ */
+uint8_t get_tri_layer_adjust_layer(void);