feat(split): wired split over serial support

app/include/zmk/split/bluetooth/central.h

@@ -8,8 +8,8 @@
 #include <zmk/hid_indicators_types.h>
 #endif // IS_ENABLED(CONFIG_ZMK_SPLIT_PERIPHERAL_HID_INDICATORS)
 
-int zmk_split_bt_invoke_behavior(uint8_t source, struct zmk_behavior_binding *binding,
-                                 struct zmk_behavior_binding_event event, bool state);
+int zmk_split_invoke_behavior(uint8_t source, struct zmk_behavior_binding *binding,
+                              struct zmk_behavior_binding_event event, bool state);
 
 #if IS_ENABLED(CONFIG_ZMK_SPLIT_PERIPHERAL_HID_INDICATORS)
 

app/include/zmk/split/central.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2023 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <zmk/events/position_state_changed.h>
+#include <zmk/events/sensor_event.h>
+#include <zmk/split/service.h>
+
+void zmk_position_state_change_handle(struct zmk_position_state_changed *ev);
+
+#if ZMK_KEYMAP_HAS_SENSORS
+void zmk_sensor_event_handle(struct zmk_sensor_event *ev);
+#endif
+
+void send_split_run_impl(struct zmk_split_run_behavior_payload_wrapper *payload_wrapper);

app/include/zmk/split/serial/serial.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2023 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#pragma once
+
+#include <zephyr/sys/ring_buffer.h>
+
+// The serial protocol is defined for payloads of up to 254 bytes. This should
+// be large enough to ensure that one message can be fully buffered.
+#define SERIAL_BUF_SIZE 300
+
+struct serial_device {
+    const struct device *dev;
+    uint8_t rx_buf[SERIAL_BUF_SIZE], tx_buf[SERIAL_BUF_SIZE];
+    struct ring_buf rx_rb, tx_rb;
+    struct k_work rx_work;
+
+#ifdef CONFIG_ZMK_SPLIT_SERIAL_UART_POLL
+    bool poll;
+    struct k_work tx_work;
+    struct k_timer rx_timer;
+#endif
+};
+
+void serial_handle_rx(uint32_t cmd, uint8_t *data, uint8_t len);

app/include/zmk/split/bluetooth/service.h → app/include/zmk/split/service.h

@@ -10,6 +10,7 @@
 #include <zmk/sensors.h>
 
 #define ZMK_SPLIT_RUN_BEHAVIOR_DEV_LEN 9
+#define ZMK_SPLIT_POS_STATE_LEN 16
 
 struct sensor_event {
     uint8_t sensor_index;
@@ -30,8 +31,18 @@ struct zmk_split_run_behavior_payload {
     char behavior_dev[ZMK_SPLIT_RUN_BEHAVIOR_DEV_LEN];
 } __packed;
 
-int zmk_split_bt_position_pressed(uint8_t position);
-int zmk_split_bt_position_released(uint8_t position);
-int zmk_split_bt_sensor_triggered(uint8_t sensor_index,
-                                  const struct zmk_sensor_channel_data channel_data[],
-                                  size_t channel_data_size);
+struct zmk_split_run_behavior_payload_wrapper {
+    uint8_t source;
+    struct zmk_split_run_behavior_payload payload;
+};
+
+int zmk_split_position_pressed(uint8_t position);
+int zmk_split_position_released(uint8_t position);
+int zmk_split_sensor_triggered(uint8_t sensor_index,
+                               const struct zmk_sensor_channel_data channel_data[],
+                               size_t channel_data_size);
+
+void send_position_state_impl(uint8_t *state, int len);
+#if ZMK_KEYMAP_HAS_SENSORS
+void send_sensor_state_impl(struct sensor_event *event, int len);
+#endif

app/src/keymap.c

@@ -214,15 +214,15 @@ int zmk_keymap_apply_position_state(uint8_t source, int layer, uint32_t position
         if (source == ZMK_POSITION_STATE_CHANGE_SOURCE_LOCAL) {
             return invoke_locally(&binding, event, pressed);
         } else {
-            return zmk_split_bt_invoke_behavior(source, &binding, event, pressed);
+            return zmk_split_invoke_behavior(source, &binding, event, pressed);
         }
 #else
         return invoke_locally(&binding, event, pressed);
 #endif
     case BEHAVIOR_LOCALITY_GLOBAL:
 #if ZMK_BLE_IS_CENTRAL
         for (int i = 0; i < ZMK_SPLIT_BLE_PERIPHERAL_COUNT; i++) {
-            zmk_split_bt_invoke_behavior(i, &binding, event, pressed);
+            zmk_split_invoke_behavior(i, &binding, event, pressed);
         }
 #endif
         return invoke_locally(&binding, event, pressed);

app/src/split/CMakeLists.txt

@@ -1,6 +1,23 @@
 # Copyright (c) 2022 The ZMK Contributors
 # SPDX-License-Identifier: MIT
 
+if (NOT CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
+  if (CONFIG_ZMK_SPLIT_BLE OR CONFIG_ZMK_SPLIT_SERIAL)
+    target_sources(app PRIVATE listener.c)
+    target_sources(app PRIVATE service.c)
+  endif()
+endif()
+
+if (CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
+  if (CONFIG_ZMK_SPLIT_BLE OR CONFIG_ZMK_SPLIT_SERIAL)
+    target_sources(app PRIVATE central.c)
+  endif()
+endif()
+
 if (CONFIG_ZMK_SPLIT_BLE)
     add_subdirectory(bluetooth)
-endif()
+endif()
+
+if (CONFIG_ZMK_SPLIT_SERIAL)
+    add_subdirectory(serial)
+endif()

app/src/split/Kconfig

@@ -6,19 +6,59 @@ menuconfig ZMK_SPLIT
 
 if ZMK_SPLIT
 
+config ZMK_SPLIT_INIT_PRIORITY
+    int "Split Init Priority"
+    default 50
+
 config ZMK_SPLIT_ROLE_CENTRAL
     bool "Split central device"
 
-choice ZMK_SPLIT_TRANSPORT
-    prompt "Split transport"
+if ZMK_SPLIT_ROLE_CENTRAL
+
+config ZMK_SPLIT_CENTRAL_POSITION_QUEUE_SIZE
+    int "Max number of key position state events to queue when received from peripherals"
+    default 5
+
+config ZMK_SPLIT_CENTRAL_SPLIT_RUN_STACK_SIZE
+    int "Split central write thread stack size"
+    default 512
+
+config ZMK_SPLIT_CENTRAL_SPLIT_RUN_QUEUE_SIZE
+    int "Max number of behavior run events to queue to send to the peripheral(s)"
+    default 5
+
+config ZMK_SPLIT_CENTRAL_PRIORITY
+    int "Split central thread priority"
+    default 5
+
+endif # ZMK_SPLIT_ROLE_CENTRAL
+
+if !ZMK_SPLIT_ROLE_CENTRAL
+
+config ZMK_SPLIT_PERIPHERAL_STACK_SIZE
+    int "Split peripheral notify thread stack size"
+    default 756
+
+config ZMK_SPLIT_PERIPHERAL_PRIORITY
+    int "Split peripheral notify thread priority"
+    default 5
+
+config ZMK_SPLIT_PERIPHERAL_POSITION_QUEUE_SIZE
+    int "Max number of key position state events to queue to send to the central"
+    default 10
+
+endif #!ZMK_SPLIT_ROLE_CENTRAL
 
 config ZMK_SPLIT_BLE
     bool "BLE"
+    default ZMK_SPLIT && ZMK_BLE
     depends on ZMK_BLE
     select BT_USER_PHY_UPDATE
     select BT_AUTO_PHY_UPDATE
 
-endchoice
+config ZMK_SPLIT_SERIAL
+    bool "Serial"
+    select RING_BUFFER
 
 config ZMK_SPLIT_PERIPHERAL_HID_INDICATORS
     bool "Peripheral HID Indicators"
@@ -30,3 +70,4 @@ config ZMK_SPLIT_PERIPHERAL_HID_INDICATORS
 endif
 
 rsource "bluetooth/Kconfig"
+rsource "serial/Kconfig"

app/src/split/bluetooth/CMakeLists.txt

@@ -2,14 +2,14 @@
 # SPDX-License-Identifier: MIT
 
 if (NOT CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
-  target_sources(app PRIVATE split_listener.c)
   target_sources(app PRIVATE service.c)
   target_sources(app PRIVATE peripheral.c)
 endif()
+
 if (CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
   target_sources(app PRIVATE central.c)
 endif()
 
 if (CONFIG_ZMK_SPLIT_BLE_CENTRAL_BATTERY_LEVEL_PROXY)
   target_sources(app PRIVATE central_bas_proxy.c)
-endif()
+endif()

app/src/split/bluetooth/Kconfig

@@ -46,18 +46,6 @@ config ZMK_SPLIT_BLE_CENTRAL_BATTERY_LEVEL_PROXY
 
 endif
 
-config ZMK_SPLIT_BLE_CENTRAL_POSITION_QUEUE_SIZE
-    int "Max number of key position state events to queue when received from peripherals"
-    default 5
-
-config ZMK_SPLIT_BLE_CENTRAL_SPLIT_RUN_STACK_SIZE
-    int "BLE split central write thread stack size"
-    default 512
-
-config ZMK_SPLIT_BLE_CENTRAL_SPLIT_RUN_QUEUE_SIZE
-    int "Max number of behavior run events to queue to send to the peripheral(s)"
-    default 5
-
 config ZMK_SPLIT_BLE_PREF_INT
     int "Connection interval to use for split central/peripheral connection"
     default 6
@@ -74,18 +62,6 @@ endif # ZMK_SPLIT_ROLE_CENTRAL
 
 if !ZMK_SPLIT_ROLE_CENTRAL
 
-config ZMK_SPLIT_BLE_PERIPHERAL_STACK_SIZE
-    int "BLE split peripheral notify thread stack size"
-    default 756
-
-config ZMK_SPLIT_BLE_PERIPHERAL_PRIORITY
-    int "BLE split peripheral notify thread priority"
-    default 5
-
-config ZMK_SPLIT_BLE_PERIPHERAL_POSITION_QUEUE_SIZE
-    int "Max number of key position state events to queue to send to the central"
-    default 10
-
 config BT_MAX_PAIRED
     default 1