From affe5574ecb29071620d101d5995a7eab68a45da Mon Sep 17 00:00:00 2001
From: KY-zhang-X <tjkdbd@163.com>
Date: Thu, 29 Sep 2022 11:55:58 +0800
Subject: [PATCH] hal_uart: add some details

---
 platform/hal/st/stm32l4xx/src/tos_hal_uart.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/platform/hal/st/stm32l4xx/src/tos_hal_uart.c b/platform/hal/st/stm32l4xx/src/tos_hal_uart.c
index b1d34769..4b3c31ee 100644
--- a/platform/hal/st/stm32l4xx/src/tos_hal_uart.c
+++ b/platform/hal/st/stm32l4xx/src/tos_hal_uart.c
@@ -20,6 +20,8 @@ __API__ int tos_hal_uart_init(hal_uart_t *uart, hal_uart_port_t port)
     } else if (port == HAL_UART_PORT_3) {
         uart->private_uart = &huart3;
         MX_USART3_UART_Init();
+    } else {
+        return -1;
     }
 
     return 0;