diff --git a/drivers/hwmon/lm80.c b/drivers/hwmon/lm80.c
index 0e30fa00204cdd65ad927ee38d4bb00e61b49f58..f9b8e3e23a8e8d22293b4e22ee27dc3563f13fa4 100644
--- a/drivers/hwmon/lm80.c
+++ b/drivers/hwmon/lm80.c
@@ -393,8 +393,10 @@ static ssize_t set_fan_div(struct device *dev, struct device_attribute *attr,
 	}
 
 	rv = lm80_read_value(client, LM80_REG_FANDIV);
-	if (rv < 0)
+	if (rv < 0) {
+		mutex_unlock(&data->update_lock);
 		return rv;
+	}
 	reg = (rv & ~(3 << (2 * (nr + 1))))
 	    | (data->fan_div[nr] << (2 * (nr + 1)));
 	lm80_write_value(client, LM80_REG_FANDIV, reg);