diff --git a/drivers/tty/serial/sunzilog.c b/drivers/tty/serial/sunzilog.c
index 8e916e7..5a47d1b 100644
--- a/drivers/tty/serial/sunzilog.c
+++ b/drivers/tty/serial/sunzilog.c
@@ -1397,7 +1397,7 @@
 #endif
 }
 
-static int zilog_irq = -1;
+static int zilog_irq;
 
 static int __devinit zs_probe(struct platform_device *op)
 {
@@ -1425,7 +1425,7 @@
 
 	rp = sunzilog_chip_regs[inst];
 
-	if (zilog_irq == -1)
+	if (!zilog_irq)
 		zilog_irq = op->archdata.irqs[0];
 
 	up = &sunzilog_port_table[inst * 2];
@@ -1580,7 +1580,7 @@
 	if (err)
 		goto out_unregister_uart;
 
-	if (zilog_irq != -1) {
+	if (!zilog_irq) {
 		struct uart_sunzilog_port *up = sunzilog_irq_chain;
 		err = request_irq(zilog_irq, sunzilog_interrupt, IRQF_SHARED,
 				  "zs", sunzilog_irq_chain);
@@ -1621,7 +1621,7 @@
 {
 	platform_driver_unregister(&zs_driver);
 
-	if (zilog_irq != -1) {
+	if (!zilog_irq) {
 		struct uart_sunzilog_port *up = sunzilog_irq_chain;
 
 		/* Disable Interrupts */
@@ -1637,7 +1637,7 @@
 		}
 
 		free_irq(zilog_irq, sunzilog_irq_chain);
-		zilog_irq = -1;
+		zilog_irq = 0;
 	}
 
 	if (sunzilog_reg.nr) {