diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 7592979..5a693d2 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -272,7 +272,7 @@
 #endif
 }
 
-#ifndef CONFIG_NS16550_MIN_FUNCTIONS
+#if !CONFIG_IS_ENABLED(NS16550_MIN_FUNCTIONS)
 void ns16550_reinit(struct ns16550 *com_port, int baud_divisor)
 {
 	serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
@@ -281,7 +281,7 @@
 	serial_out(ns16550_getfcr(com_port), &com_port->fcr);
 	ns16550_setbrg(com_port, baud_divisor);
 }
-#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
+#endif /* !CONFIG_IS_ENABLED(NS16550_MIN_FUNCTIONS) */
 
 void ns16550_putc(struct ns16550 *com_port, char c)
 {
@@ -299,7 +299,7 @@
 		schedule();
 }
 
-#ifndef CONFIG_NS16550_MIN_FUNCTIONS
+#if !CONFIG_IS_ENABLED(NS16550_MIN_FUNCTIONS)
 char ns16550_getc(struct ns16550 *com_port)
 {
 	while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
@@ -317,7 +317,7 @@
 	return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
 }
 
-#endif /* CONFIG_NS16550_MIN_FUNCTIONS */
+#endif /* !CONFIG_IS_ENABLED(NS16550_MIN_FUNCTIONS) */
 
 #ifdef CONFIG_DEBUG_UART_NS16550