1 files changed, 94 insertions, 0 deletions
diff --git a/keyboards/drop/lib/mux.c b/keyboards/drop/lib/mux.c
new file mode 100644
index 0000000000..85a657544f
--- /dev/null
+++ b/keyboards/drop/lib/mux.c
@@ -0,0 +1,94 @@
+// Copyright 2023 Massdrop, Inc.
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include "keyboard.h"
+#include "analog.h"
+#include "gpio.h"
+#include "wait.h"
+
+#define S_UP        B12
+#define E_UP_N      B13
+#define S_DN1       B14
+#define E_DN1_N     B15
+#define E_VBUS_1    A8
+#define E_VBUS_2    A15
+#define SRC_1       B8
+#define SRC_2       B9
+#define HUB_RESET_N D2
+#define IRST        B1
+#define SDB_N       B2
+#define C1_A5_SENSE A4
+#define C1_B5_SENSE A7
+#define C2_A5_SENSE C4
+#define C2_B5_SENSE B0
+
+static inline void digital_write(pin_t pin, uint8_t level) {
+    setPinOutput(pin);
+    writePin(pin, level);
+}
+
+uint16_t v_con_1 = 0;
+uint16_t v_con_2 = 0;
+uint16_t v_con_3 = 0;
+uint16_t v_con_4 = 0;
+
+void keyboard_USB_enable(void) {
+    // initial state
+    digital_write(S_UP, 0);
+    digital_write(E_UP_N, 1);
+    digital_write(S_DN1, 1);
+    digital_write(E_DN1_N, 1);
+    digital_write(E_VBUS_1, 0);
+    digital_write(E_VBUS_2, 0);
+    digital_write(SRC_1, 1);
+    digital_write(SRC_2, 1);
+
+    setPinInput(C1_A5_SENSE);
+    setPinInput(C1_B5_SENSE);
+    setPinInput(C2_A5_SENSE);
+    setPinInput(C2_B5_SENSE);
+
+    // reset hub
+    digital_write(HUB_RESET_N, 0);
+    wait_ms(100);
+    digital_write(HUB_RESET_N, 1);
+
+    wait_ms(500); // Allow power dissipation time on CC lines
+
+    v_con_1 = analogReadPin(C1_A5_SENSE);
+    v_con_2 = analogReadPin(C1_B5_SENSE);
+    v_con_3 = analogReadPin(C2_A5_SENSE);
+    v_con_4 = analogReadPin(C2_B5_SENSE);
+
+    // TODO: dynamic port port configure logic?
+    digital_write(E_UP_N, 0);   // HOST enable
+    digital_write(E_DN1_N, 0);  // EXTRA enable
+    digital_write(E_VBUS_1, 1); // USBC-1 enable full power I/O
+    digital_write(E_VBUS_2, 1); // USBC-2 enable full power I/O
+
+    if ((v_con_1 + v_con_2) > (v_con_3 + v_con_4)) {
+        digital_write(S_UP, 0);  // HOST to USBC-1
+        digital_write(S_DN1, 1); // EXTRA to USBC-2
+        digital_write(SRC_1, 1); // HOST on USBC-1
+        digital_write(SRC_2, 0); // EXTRA available on USBC-2
+    } else {
+        digital_write(S_UP, 1);  // EXTRA to USBC-1
+        digital_write(S_DN1, 0); // HOST to USBC-2
+        digital_write(SRC_1, 0); // EXTRA available on USBC-1
+        digital_write(SRC_2, 1); // HOST on USBC-2
+    }
+}
+
+void keyboard_ISSI_enable(void) {
+#ifdef RGB_MATRIX_ENABLE
+    digital_write(IRST, 0);
+    digital_write(SDB_N, 1);
+#endif
+}
+
+
+void keyboard_pre_init_kb(void) {
+    keyboard_USB_enable();
+    keyboard_ISSI_enable();
+
+    keyboard_pre_init_user();
+}