serial: mrst_max3110: Check the irq number before enable/disabe irq in PM hooks

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/tty/serial/mrst_max3110.c b/drivers/tty/serial/mrst_max3110.c
index a67e7081f001..ee77e7366ed6 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;
 }