feat(split): wired split over serial TX support (WIP 2024-05-26)

Author: xudongzheng

app/src/split/serial/CMakeLists.txt

@@ -1,6 +1,10 @@
 # Copyright (c) 2023 The ZMK Contributors
 # SPDX-License-Identifier: MIT
 
+if (NOT CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
+  target_sources(app PRIVATE peripheral.c)
+endif()
+
 if (CONFIG_ZMK_SPLIT_ROLE_CENTRAL)
   target_sources(app PRIVATE central.c)
 endif()

app/src/split/serial/peripheral.c

@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2023 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <zephyr/kernel.h>
+
+#include <zmk/split/serial/serial.h>
+
+// TODO TODO TODO
+#include <zephyr/logging/log.h>
+LOG_MODULE_DECLARE(slicemk);
+
+// TODO TODO TODO these two should be in a header somewhere
+
+// TODO TODO TODO implement central to peripheral data transfer
+void serial_handle_rx(uint32_t cmd, uint8_t *data, uint8_t len) {
+    LOG_HEXDUMP_ERR(data, len, "central to peripheral");
+}
+
+void send_position_state_impl(uint8_t *state, int len) {
+    serial_write_uart(0x73627400, state, len);
+}

app/src/split/serial/serial.c

@@ -117,7 +117,7 @@ static void serial_callback(const struct device *dev, void *data) {
     }
 }
 
-void serial_write(struct serial_device *sd, uint32_t cmd, uint8_t *data, uint8_t len) {
+static void serial_write(struct serial_device *sd, uint32_t cmd, uint8_t *data, uint8_t len) {
     // TODO TODO TODO use buf with size SERIAL_BUF_SIZE. do single
     // ring_buf_put() to avoid potential race
     uint8_t header[13] = SERIAL_MSG_PREFIX;
@@ -138,6 +138,13 @@ void serial_write(struct serial_device *sd, uint32_t cmd, uint8_t *data, uint8_t
     uart_irq_tx_enable(sd->dev);
 }
 
+// TODO TODO TODO this should be abstracted a bit differently
+#ifdef CONFIG_ZMK_SPLIT_SERIAL_UART
+void serial_write_uart(uint32_t cmd, uint8_t *data, uint8_t len) {
+    serial_write(&serial_devs[0], cmd, data, len);
+}
+#endif
+
 #ifdef CONFIG_ZMK_SPLIT_SERIAL_UART_POLL
 
 static void serial_tx_work_handler(struct k_work *work) {