Input: hyperv-keyboard - register as a wakeup source

With this patch, we can press a key to wake up the VM after the VM executes
"echo freeze > /sys/power/state".

Signed-off-by: Dexuan Cui <[e-mail]>
Signed-off-by: K. Y. Srinivasan <[e-mail]>
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/serio/hyperv-keyboard.c

···
 			serio_interrupt(kbd_dev->hv_serio, scan_code, 0);
 		}
 		spin_unlock_irqrestore(&kbd_dev->lock, flags);
+
+		/*
+		 * Only trigger a wakeup on key down, otherwise
+		 * "echo freeze > /sys/power/state" can't really enter the
+		 * state because the Enter-UP can trigger a wakeup at once.
+		 */
+		if (!(info & IS_BREAK))
+			pm_wakeup_event(&hv_dev->device, 0);
+
 		break;
 
 	default:
···
 		goto err_close_vmbus;
 
 	serio_register_port(kbd_dev->hv_serio);
+
+	device_init_wakeup(&hv_dev->device, true);
+
 	return 0;
 
 err_close_vmbus:
···
 {
 	struct hv_kbd_dev *kbd_dev = hv_get_drvdata(hv_dev);
 
+	device_init_wakeup(&hv_dev->device, false);
 	serio_unregister_port(kbd_dev->hv_serio);
 	vmbus_close(hv_dev->channel);
 	kfree(kbd_dev);