diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 3d376d7580..9b044a37da 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -65,6 +65,8 @@ static inline void serial_out_shift(void *addr, int shift, int value)
 	out_le32(addr, value);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	out_be32(addr, value);
+#elif defined(CONFIG_SYS_NS16550_MEM32)
+	writel(value, addr);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
 	writeb(value, addr + (1 << shift) - 1);
 #else
@@ -80,6 +82,8 @@ static inline int serial_in_shift(void *addr, int shift)
 	return in_le32(addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	return in_be32(addr);
+#elif defined(CONFIG_SYS_NS16550_MEM32)
+	return readl(addr);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
 	return readb(addr + (1 << shift) - 1);
 #else
diff --git a/include/ns16550.h b/include/ns16550.h
index 0607379537..4e620676c4 100644
--- a/include/ns16550.h
+++ b/include/ns16550.h
@@ -33,7 +33,7 @@
 
 #if !defined(CONFIG_SYS_NS16550_REG_SIZE) || (CONFIG_SYS_NS16550_REG_SIZE == 0)
 #error "Please define NS16550 registers size."
-#elif defined(CONFIG_SYS_NS16550_MEM32)
+#elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_DM_SERIAL)
 #define UART_REG(x) u32 x
 #elif (CONFIG_SYS_NS16550_REG_SIZE > 0)
 #define UART_REG(x)						   \