diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index 70c9462..57e6125 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -55,17 +55,9 @@ DECLARE_GLOBAL_DATA_PTR;
 #endif /* CONFIG_SYS_NS16550_IER */
 
 #ifdef CONFIG_DM_SERIAL
-static void ns16550_writeb(NS16550_t port, int offset, int value)
-{
-	struct ns16550_platdata *plat = port->plat;
-	unsigned char *addr;
 
-	offset *= 1 << plat->reg_shift;
-	addr = map_sysmem(plat->base, 0) + offset;
-	/*
-	 * As far as we know it doesn't make sense to support selection of
-	 * these options at run-time, so use the existing CONFIG options.
-	 */
+static inline void serial_out_shift(unsigned char *addr, int shift, int value)
+{
 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
 	outb(value, (ulong)addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
@@ -73,19 +65,14 @@ static void ns16550_writeb(NS16550_t port, int offset, int value)
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	out_be32(addr, value);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
-	writeb(value, addr + (1 << plat->reg_shift) - 1);
+	writeb(value, addr + (1 << shift) - 1);
 #else
 	writeb(value, addr);
 #endif
 }
 
-static int ns16550_readb(NS16550_t port, int offset)
+static inline int serial_in_shift(unsigned char *addr, int shift)
 {
-	struct ns16550_platdata *plat = port->plat;
-	unsigned char *addr;
-
-	offset *= 1 << plat->reg_shift;
-	addr = map_sysmem(plat->base, 0) + offset;
 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
 	return inb((ulong)addr);
 #elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_SYS_BIG_ENDIAN)
@@ -93,12 +80,37 @@ static int ns16550_readb(NS16550_t port, int offset)
 #elif defined(CONFIG_SYS_NS16550_MEM32) && defined(CONFIG_SYS_BIG_ENDIAN)
 	return in_be32(addr);
 #elif defined(CONFIG_SYS_BIG_ENDIAN)
-	return readb(addr + (1 << plat->reg_shift) - 1);
+	return readb(addr + (1 << reg_shift) - 1);
 #else
 	return readb(addr);
 #endif
 }
 
+static void ns16550_writeb(NS16550_t port, int offset, int value)
+{
+	struct ns16550_platdata *plat = port->plat;
+	unsigned char *addr;
+
+	offset *= 1 << plat->reg_shift;
+	addr = map_sysmem(plat->base, 0) + offset;
+	/*
+	 * As far as we know it doesn't make sense to support selection of
+	 * these options at run-time, so use the existing CONFIG options.
+	 */
+	serial_out_shift(addr, plat->reg_shift, value);
+}
+
+static int ns16550_readb(NS16550_t port, int offset)
+{
+	struct ns16550_platdata *plat = port->plat;
+	unsigned char *addr;
+
+	offset *= 1 << plat->reg_shift;
+	addr = map_sysmem(plat->base, 0) + offset;
+
+	return serial_in_shift(addr, plat->reg_shift);
+}
+
 /* We can clean these up once everything is moved to driver model */
 #define serial_out(value, addr)	\
 	ns16550_writeb(com_port, addr - (unsigned char *)com_port, value)