diff --git a/drivers/hwmon/smsc47m192.c b/drivers/hwmon/smsc47m192.c
index efee4c5..34b9a60 100644
--- a/drivers/hwmon/smsc47m192.c
+++ b/drivers/hwmon/smsc47m192.c
@@ -86,7 +86,7 @@
  */
 static inline s8 TEMP_TO_REG(int val)
 {
-	return clamp_val(SCALE(val, 1, 1000), -128000, 127000);
+	return SCALE(clamp_val(val, -128000, 127000), 1, 1000);
 }
 
 static inline int TEMP_FROM_REG(s8 val)
@@ -384,6 +384,8 @@
 	err = kstrtoul(buf, 10, &val);
 	if (err)
 		return err;
+	if (val > 255)
+		return -EINVAL;
 
 	data->vrm = val;
 	return count;