modbus: cancel the server_work in modbus disable

Allow to periodically initializes/disables the modbus interface.
Switch from modbus line discipline to serial and switch back to modbus.
This can be required when the serial is shared by two sensors

Signed-off-by: Michael Trimarchi <[email protected]>

Author: panicking

subsys/modbus/modbus_core.c

@@ -338,6 +338,7 @@ int modbus_init_client(const int iface, struct modbus_iface_param param)
 int modbus_disable(const uint8_t iface)
 {
 	struct modbus_context *ctx;
+	struct k_work_sync work_sync;
 
 	ctx = modbus_get_context(iface);
 	if (ctx == NULL) {
@@ -358,6 +359,7 @@ int modbus_disable(const uint8_t iface)
 		LOG_ERR("Unknown MODBUS mode");
 	}
 
+	k_work_cancel_sync(&ctx->server_work, &work_sync);
 	ctx->rxwait_to = 0;
 	ctx->unit_id = 0;
 	ctx->mode = MODBUS_MODE_RTU;