platform/x86: surfacepro3: Support for wakeup from suspend-to-idle

Modify surface_button_notify() to make it wake up the system from
suspend-to-idle (by reporting "hard" wakeup events while suspended)
and add wakeup initialization to surface_button_add() for wakeup
events reported by this driver to work at all.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=198389
Reported-by: Valentin Manea <valy@mrs.ro>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Valentin Manea <valy@mrs.ro>

drivers/platform/x86/surfacepro3_button.c

@@ -119,7 +119,7 @@ static void surface_button_notify(struct acpi_device *device, u32 event)
 	if (key_code == KEY_RESERVED)
 		return;
 	if (pressed)
-		pm_wakeup_event(&device->dev, 0);
+		pm_wakeup_dev_event(&device->dev, 0, button->suspended);
 	if (button->suspended)
 		return;
 	input_report_key(input, key_code, pressed?1:0);
@@ -185,6 +185,8 @@ static int surface_button_add(struct acpi_device *device)
 	error = input_register_device(input);
 	if (error)
 		goto err_free_input;
+
+	device_init_wakeup(&device->dev, true);
 	dev_info(&device->dev,
 			"%s [%s]\n", name, acpi_device_bid(device));
 	return 0;