Function devm_gpiod_get_optional() returns an ERR_PTR on failure. Its
return value should not be validated by a NULL check. Instead, use IS_ERR.
Signed-off-by: Pan Bian <bianpan2016@163.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
        chip->reset_gpio = devm_gpiod_get_optional(chip->dev, "reset",
                                                   GPIOD_OUT_LOW);
 
-       if (!chip->reset_gpio) {
+       if (IS_ERR(chip->reset_gpio)) {
                dev_dbg(chip->dev, "No reset GPIO defined\n");
                return;
        }