diff --git a/drivers/serial/m32r_sio.c b/drivers/serial/m32r_sio.c
index 6e09c8b..348ee2c 100644
--- a/drivers/serial/m32r_sio.c
+++ b/drivers/serial/m32r_sio.c
@@ -539,7 +539,7 @@
 static int serial_link_irq_chain(struct uart_sio_port *up)
 {
 	struct irq_info *i = irq_lists + up->port.irq;
-	int ret, irq_flags = up->port.flags & UPF_SHARE_IRQ ? IRQF_SHARED : 0;
+	int ret, irq_flags = 0;
 
 	spin_lock_irq(&i->lock);
 
diff --git a/drivers/serial/m32r_sio.h b/drivers/serial/m32r_sio.h
index 849f1b2..e9b7e11 100644
--- a/drivers/serial/m32r_sio.h
+++ b/drivers/serial/m32r_sio.h
@@ -46,9 +46,3 @@
 #define PROBE_ANY	(~0)
 
 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
-
-#ifdef CONFIG_SERIAL_SIO_SHARE_IRQ
-#define M32R_SIO_SHARE_IRQS 1
-#else
-#define M32R_SIO_SHARE_IRQS 0
-#endif