diff --git a/targets/TARGET_GigaDevice/TARGET_GD32E10X/can_api.c b/targets/TARGET_GigaDevice/TARGET_GD32E10X/can_api.c
index df449bbad8..1b7bfe0754 100644
--- a/targets/TARGET_GigaDevice/TARGET_GD32E10X/can_api.c
+++ b/targets/TARGET_GigaDevice/TARGET_GD32E10X/can_api.c
@@ -305,7 +305,7 @@ void can_free(can_t *obj)
  */
 int can_frequency(can_t *obj, int hz)
 {
-    int reval;
+    int reval = 0;
 
     /* The maximum baud rate support to 1M */
     if (hz <= 1000000) {
diff --git a/targets/TARGET_GigaDevice/TARGET_GD32F30X/can_api.c b/targets/TARGET_GigaDevice/TARGET_GD32F30X/can_api.c
index b93a5cf1ce..db92b9db4d 100644
--- a/targets/TARGET_GigaDevice/TARGET_GD32F30X/can_api.c
+++ b/targets/TARGET_GigaDevice/TARGET_GD32F30X/can_api.c
@@ -305,7 +305,7 @@ void can_free(can_t *obj)
  */
 int can_frequency(can_t *obj, int hz)
 {
-    int reval;
+    int reval = 0;
 
     /* The maximum baud rate support to 1M */
     if (hz <= 1000000) {
diff --git a/targets/TARGET_GigaDevice/TARGET_GD32F4XX/can_api.c b/targets/TARGET_GigaDevice/TARGET_GD32F4XX/can_api.c
index 65a5ed54d4..15c67b1726 100644
--- a/targets/TARGET_GigaDevice/TARGET_GD32F4XX/can_api.c
+++ b/targets/TARGET_GigaDevice/TARGET_GD32F4XX/can_api.c
@@ -306,7 +306,7 @@ void can_free(can_t *obj)
  */
 int can_frequency(can_t *obj, int hz)
 {
-    int reval;
+    int reval = 0;
 
     /* The maximum baud rate support to 1M */
     if (hz <= 1000000) {