diff --git a/arch/sh/kernel/cpu/sh3/setup-sh770x.c b/arch/sh/kernel/cpu/sh3/setup-sh770x.c
index 592cd9ab30c4..59a88611df55 100644
--- a/arch/sh/kernel/cpu/sh3/setup-sh770x.c
+++ b/arch/sh/kernel/cpu/sh3/setup-sh770x.c
@@ -111,7 +111,6 @@ static struct platform_device rtc_device = {
 static struct plat_sci_port scif0_platform_data = {
 	.type		= PORT_SCI,
 	.ops		= &sh770x_sci_port_ops,
-	.regshift	= 1,
 };
 
 static struct resource scif0_resources[] = {
diff --git a/arch/sh/kernel/cpu/sh4/setup-sh7750.c b/arch/sh/kernel/cpu/sh4/setup-sh7750.c
index d98a55416306..57d30689204d 100644
--- a/arch/sh/kernel/cpu/sh4/setup-sh7750.c
+++ b/arch/sh/kernel/cpu/sh4/setup-sh7750.c
@@ -39,11 +39,10 @@ static struct platform_device rtc_device = {
 
 static struct plat_sci_port sci_platform_data = {
 	.type		= PORT_SCI,
-	.regshift	= 2,
 };
 
 static struct resource sci_resources[] = {
-	DEFINE_RES_MEM(0xffe00000, 0x100),
+	DEFINE_RES_MEM(0xffe00000, 0x20),
 	DEFINE_RES_IRQ(evt2irq(0x4e0)),
 };
 
diff --git a/arch/sh/kernel/cpu/sh4/setup-sh7760.c b/arch/sh/kernel/cpu/sh4/setup-sh7760.c
index 0c0cdfc69dcc..e51fe1734e13 100644
--- a/arch/sh/kernel/cpu/sh4/setup-sh7760.c
+++ b/arch/sh/kernel/cpu/sh4/setup-sh7760.c
@@ -200,12 +200,18 @@ static struct platform_device scif2_device = {
 };
 
 static struct plat_sci_port scif3_platform_data = {
+	/*
+	 * This is actually a SIM card module serial port, based on an SCI with
+	 * additional registers. The sh-sci driver doesn't support the SIM port
+	 * type, declare it as a SCI. Don't declare the additional registers in
+	 * the memory resource or the driver will compute an incorrect regshift
+	 * value.
+	 */
 	.type		= PORT_SCI,
-	.regshift	= 2,
 };
 
 static struct resource scif3_resources[] = {
-	DEFINE_RES_MEM(0xfe480000, 0x100),
+	DEFINE_RES_MEM(0xfe480000, 0x10),
 	DEFINE_RES_IRQ(evt2irq(0xc00)),
 	DEFINE_RES_IRQ(evt2irq(0xc20)),
 	DEFINE_RES_IRQ(evt2irq(0xc40)),
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index a04ed40279d1..a18f4cb8e1fb 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -2574,9 +2574,15 @@ static int sci_init_single(struct platform_device *dev,
 
 	port->type		= p->type;
 	port->flags		= UPF_FIXED_PORT | UPF_BOOT_AUTOCONF | p->flags;
-	port->regshift		= p->regshift;
 	port->fifosize		= sci_port->params->fifosize;
 
+	if (port->type == PORT_SCI) {
+		if (sci_port->reg_size >= 0x20)
+			port->regshift = 2;
+		else
+			port->regshift = 1;
+	}
+
 	/*
 	 * The UART port needs an IRQ value, so we peg this to the RX IRQ
 	 * for the multi-IRQ ports, which is where we are primarily
diff --git a/include/linux/serial_sci.h b/include/linux/serial_sci.h
index f9a4526f4ec5..e598eaef3962 100644
--- a/include/linux/serial_sci.h
+++ b/include/linux/serial_sci.h
@@ -56,7 +56,6 @@ struct plat_sci_port {
 	/*
 	 * Platform overrides if necessary, defaults otherwise.
 	 */
-	unsigned char	regshift;
 	unsigned char	regtype;
 
 	struct plat_sci_port_ops	*ops;