diff --git a/drivers/tty/serial/lantiq.c b/drivers/tty/serial/lantiq.c
index 93ac04686eb95f63e52052262fb591c4bbeea687..88d01e0bb0c8e34122e0ab7c0f26d1e48b78bd13 100644
--- a/drivers/tty/serial/lantiq.c
+++ b/drivers/tty/serial/lantiq.c
@@ -318,7 +318,7 @@ lqasc_startup(struct uart_port *port)
 	struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
 	int retval;
 
-	if (ltq_port->clk)
+	if (!IS_ERR(ltq_port->clk))
 		clk_enable(ltq_port->clk);
 	port->uartclk = clk_get_rate(ltq_port->fpiclk);
 
@@ -386,7 +386,7 @@ lqasc_shutdown(struct uart_port *port)
 		port->membase + LTQ_ASC_RXFCON);
 	ltq_w32_mask(ASCTXFCON_TXFEN, ASCTXFCON_TXFFLU,
 		port->membase + LTQ_ASC_TXFCON);
-	if (ltq_port->clk)
+	if (!IS_ERR(ltq_port->clk))
 		clk_disable(ltq_port->clk);
 }