staging: unisys: visorbus: add error handling visorbus_enable_channel_interrupt

Add error handling to visorbus_enable_channel_interrupt.
Signed-off-by: David Kershner <david.kershner@unisys.com>
Reviewed-by: Reviewed-by: Tim Sell <timothy.sell@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/include/visorbus.h

@@ -180,7 +180,7 @@ int visorbus_read_channel(struct visor_device *dev,
 int visorbus_write_channel(struct visor_device *dev,
 			   unsigned long offset, void *src,
 			   unsigned long nbytes);
-void visorbus_enable_channel_interrupts(struct visor_device *dev);
+int visorbus_enable_channel_interrupts(struct visor_device *dev);
 void visorbus_disable_channel_interrupts(struct visor_device *dev);
 
 /* Levels of severity for diagnostic events, in order from lowest severity to

drivers/staging/unisys/visorbus/visorbus_main.c

@@ -580,17 +580,17 @@ EXPORT_SYMBOL_GPL(visorbus_write_channel);
  * Currently we don't yet have a real interrupt, so for now we just call the
  * interrupt function periodically via a timer.
  */
-void
+int
 visorbus_enable_channel_interrupts(struct visor_device *dev)
 {
 	struct visor_driver *drv = to_visor_driver(dev->device.driver);
 
 	if (!drv->channel_interrupt) {
 		dev_err(&dev->device, "%s no interrupt function!\n", __func__);
-		return;
+		return -ENOENT;
 	}
 
-	dev_start_periodic_work(dev);
+	return dev_start_periodic_work(dev);
 }
 EXPORT_SYMBOL_GPL(visorbus_enable_channel_interrupts);