1 files changed, 40 insertions, 0 deletions
diff --git a/keyboards/matrix/m20add/tca6424.h b/keyboards/matrix/m20add/tca6424.h
new file mode 100644
index 000000000..6153265ed
--- /dev/null
+++ b/keyboards/matrix/m20add/tca6424.h
@@ -0,0 +1,40 @@
+/**
+ * @file tca6424.h
+ * @author astro
+ * @brief  driver for the tca6424
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#ifndef TCA6424_ADDR
+    #define TCA6424_ADDR 0x44
+#endif
+
+typedef enum {
+    TCA6424_PORT0 = 0,
+    TCA6424_PORT1,
+    TCA6424_PORT2,
+} TCA6424_PORT;
+
+void tca6424_init(void);
+
+void    tca6424_write_config(TCA6424_PORT port, uint8_t data);
+void    tca6424_write_polarity(TCA6424_PORT port, uint8_t data);
+
+void    tca6424_write_port(TCA6424_PORT port, uint8_t data);
+uint8_t tca6424_read_port(TCA6424_PORT port);