diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index f082e48ab1139..70d62f5bc9092 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -215,7 +215,7 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len)
 	int i;
 
 	if (send_command(cmd) || send_argument(key)) {
-		pr_warn("%s: read arg fail\n", key);
+		pr_warn("%.4s: read arg fail\n", key);
 		return -EIO;
 	}
 
@@ -223,7 +223,7 @@ static int read_smc(u8 cmd, const char *key, u8 *buffer, u8 len)
 
 	for (i = 0; i < len; i++) {
 		if (__wait_status(0x05)) {
-			pr_warn("%s: read data fail\n", key);
+			pr_warn("%.4s: read data fail\n", key);
 			return -EIO;
 		}
 		buffer[i] = inb(APPLESMC_DATA_PORT);