feat(slave_node): Refine Modbus UART and add CDC-ACM support

- Adjusted Device Tree Overlays for bluepill_f103rb and weact_stm32g431_core
  to correctly define Modbus UART via 'modbus0' subnode with 'zephyr,modbus-serial'
  compatibility, aligning with rtu_server sample.
- Prepared modbus_server.c to use the correct Device Tree node for Modbus UART.

software/apps/slave_node/boards/bluepill_f103rb.overlay

@@ -12,6 +12,7 @@
         label = "RTT";
         status = "okay";
     };
+
 };
 
 &flash0 {
@@ -34,7 +35,10 @@
     };
 };
 
-&usart1 {
+ &usart1: {
+    pinctrl-0 = <&usart1_tx_pa9 &usart1_rx_pa10>;
+    pinctrl-names = "default";
+
     modbus0 {
         compatible = "zephyr,modbus-serial";
         status = "okay";

software/apps/slave_node/boards/weact_stm32g431_core.overlay

@@ -1,9 +1,10 @@
 &usart1 {
+    pinctrl-0 = <&usart1_tx_pa9 &usart1_rx_pa10>;
+    pinctrl-names = "default";
+
     modbus0 {
         compatible = "zephyr,modbus-serial";
         status = "okay";
     };
     status = "okay";
-    pinctrl-0 = <&usart1_tx_pa9 &usart1_rx_pa10>;
-    pinctrl-names = "default";
 };

software/modules/modbus_server/src/modbus_server.c

@@ -7,6 +7,9 @@
 #include "valve.h"
 #include "fwu.h"
 
+
+#include <zephyr/usb/usb_device.h>
+
 LOG_MODULE_REGISTER(modbus_server, LOG_LEVEL_INF);
 
 static int modbus_iface;
@@ -27,7 +30,8 @@ static void watchdog_timer_handler(struct k_timer *timer_id)
 
 static inline void reset_watchdog(void)
 {
-	if (watchdog_timeout_s > 0) {
+	if (watchdog_timeout_s > 0)
+	{
 		k_timer_start(&watchdog_timer, K_SECONDS(watchdog_timeout_s), K_NO_WAIT);
 	}
 }
@@ -35,11 +39,20 @@ static inline void reset_watchdog(void)
 static int holding_reg_rd(uint16_t addr, uint16_t *reg)
 {
 	reset_watchdog();
-	switch (addr) {
+	switch (addr)
-	case REG_HOLDING_MAX_OPENING_TIME_S: *reg = valve_get_max_open_time(); break;
+	{
-	case REG_HOLDING_MAX_CLOSING_TIME_S: *reg = valve_get_max_close_time(); break;
+	case REG_HOLDING_MAX_OPENING_TIME_S:
-	case REG_HOLDING_WATCHDOG_TIMEOUT_S: *reg = watchdog_timeout_s; break;
+		*reg = valve_get_max_open_time();
-	default: *reg = 0; break;
+		break;
+	case REG_HOLDING_MAX_CLOSING_TIME_S:
+		*reg = valve_get_max_close_time();
+		break;
+	case REG_HOLDING_WATCHDOG_TIMEOUT_S:
+		*reg = watchdog_timeout_s;
+		break;
+	default:
+		*reg = 0;
+		break;
 	}
 	return 0;
 }
@@ -47,11 +60,21 @@ static int holding_reg_rd(uint16_t addr, uint16_t *reg)
 static int holding_reg_wr(uint16_t addr, uint16_t reg)
 {
 	reset_watchdog();
-	switch (addr) {
+	switch (addr)
+	{
 	case REG_HOLDING_VALVE_COMMAND:
-		if (reg == 1) { valve_open(); }
+		if (reg == 1)
-		else if (reg == 2) { valve_close(); }
+		{
-		else if (reg == 0) { valve_stop(); }
+			valve_open();
+		}
+		else if (reg == 2)
+		{
+			valve_close();
+		}
+		else if (reg == 0)
+		{
+			valve_stop();
+		}
 		break;
 	case REG_HOLDING_MAX_OPENING_TIME_S:
 		valve_set_max_open_time(reg);
@@ -61,16 +84,20 @@ static int holding_reg_wr(uint16_t addr, uint16_t reg)
 		break;
 	case REG_HOLDING_WATCHDOG_TIMEOUT_S:
 		watchdog_timeout_s = reg;
-		if (watchdog_timeout_s > 0) {
+		if (watchdog_timeout_s > 0)
+		{
 			LOG_INF("Watchdog enabled with %u s timeout.", watchdog_timeout_s);
 			reset_watchdog();
-		} else {
+		}
+		else
+		{
 			LOG_INF("Watchdog disabled.");
 			k_timer_stop(&watchdog_timer);
 		}
 		break;
 	case REG_HOLDING_DEVICE_RESET:
-		if (reg == 1) {
+		if (reg == 1)
+		{
 			LOG_WRN("Modbus reset command received. Rebooting...");
 			sys_reboot(SYS_REBOOT_WARM);
 		}
@@ -86,13 +113,26 @@ static int input_reg_rd(uint16_t addr, uint16_t *reg)
 {
 	reset_watchdog();
 	uint32_t uptime_s = k_uptime_get_32() / 1000;
-	switch (addr) {
+	switch (addr)
-	case REG_INPUT_VALVE_STATE_MOVEMENT: *reg = (valve_get_movement() << 8) | (valve_get_state() & 0xFF); break;
+	{
-	case REG_INPUT_MOTOR_CURRENT_MA: *reg = valve_get_motor_current(); break;
+	case REG_INPUT_VALVE_STATE_MOVEMENT:
-	case REG_INPUT_UPTIME_SECONDS_LOW: *reg = (uint16_t)(uptime_s & 0xFFFF); break;
+		*reg = (valve_get_movement() << 8) | (valve_get_state() & 0xFF);
-	case REG_INPUT_UPTIME_SECONDS_HIGH: *reg = (uint16_t)(uptime_s >> 16); break;
+		break;
-	case REG_INPUT_FWU_LAST_CHUNK_CRC: *reg = fwu_get_last_chunk_crc(); break;
+	case REG_INPUT_MOTOR_CURRENT_MA:
-	default: *reg = 0; break;
+		*reg = valve_get_motor_current();
+		break;
+	case REG_INPUT_UPTIME_SECONDS_LOW:
+		*reg = (uint16_t)(uptime_s & 0xFFFF);
+		break;
+	case REG_INPUT_UPTIME_SECONDS_HIGH:
+		*reg = (uint16_t)(uptime_s >> 16);
+		break;
+	case REG_INPUT_FWU_LAST_CHUNK_CRC:
+		*reg = fwu_get_last_chunk_crc();
+		break;
+	default:
+		*reg = 0;
+		break;
 	}
 	return 0;
 }
@@ -109,8 +149,28 @@ int modbus_server_init(void)
 {
 	k_timer_init(&watchdog_timer, watchdog_timer_handler, NULL);
 	const char iface_name[] = {DEVICE_DT_NAME(MODBUS_NODE)};
+#if DT_NODE_HAS_COMPAT(DT_PARENT(MODBUS_NODE), zephyr_cdc_acm_uart)
+	const struct device *const dev = DEVICE_DT_GET(DT_PARENT(MODBUS_NODE));
+	uint32_t dtr = 0;
+
+	if (!device_is_ready(dev) || usb_enable(NULL))
+	{
+		return 0;
+	}
+
+	while (!dtr)
+	{
+		uart_line_ctrl_get(dev, UART_LINE_CTRL_DTR, &dtr);
+		k_sleep(K_MSEC(100));
+	}
+
+	LOG_INF("Client connected to server on %s", dev->name);
+#endif
 	modbus_iface = modbus_iface_get_by_name(iface_name);
-	if (modbus_iface < 0) { return modbus_iface; }
+	if (modbus_iface < 0)
+	{
+		return modbus_iface;
+	}
 	server_param.server.user_cb = &mbs_cbs;
 	return modbus_init_server(modbus_iface, server_param);
 }
@@ -122,7 +182,8 @@ int modbus_reconfigure(uint32_t baudrate, uint8_t unit_id)
 
 	int ret = modbus_init_server(modbus_iface, server_param);
 
-    if (ret == 0) {
+	if (ret == 0)
+	{
 		settings_save_one("modbus/baudrate", &baudrate, sizeof(baudrate));
 		settings_save_one("modbus/unit_id", &unit_id, sizeof(unit_id));
 	}