[PATCH 1/2] serial: mrst_max3110: Check the irq number before enable/disabe irq in PM hooks

[Feng Tang <feng.tang@intel.com>]

We should check the validity of the irq number before calling
disable_irq() and enable_irq() in the suspend/resume function,
as "max->irq == 0" means the irq is not enabled for max3110
device, otherwise it will hurt device whose irq number is really 0.

Signed-off-by: Feng Tang <feng.tang@intel.com>
---
 drivers/tty/serial/mrst_max3110.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/mrst_max3110.c b/drivers/tty/serial/mrst_max3110.c
index a67e708..ee77e73 100644
--- a/drivers/tty/serial/mrst_max3110.c
+++ b/drivers/tty/serial/mrst_max3110.c
@@ -749,7 +749,8 @@ static int serial_m3110_suspend(struct device *dev)
 	struct spi_device *spi = to_spi_device(dev);
 	struct uart_max3110 *max = spi_get_drvdata(spi);
 
-	disable_irq(max->irq);
+	if (max->irq > 0)
+		disable_irq(max->irq);
 	uart_suspend_port(&serial_m3110_reg, &max->port);
 	max3110_out(max, max->cur_conf | WC_SW_SHDI);
 	return 0;
@@ -762,7 +763,8 @@ static int serial_m3110_resume(struct device *dev)
 
 	max3110_out(max, max->cur_conf);
 	uart_resume_port(&serial_m3110_reg, &max->port);
-	enable_irq(max->irq);
+	if (max->irq > 0)
+		enable_irq(max->irq);
 	return 0;
 }
 
-- 
1.7.0.4