[PATCH v2 2/5] USB: Export usb_wakeup_enabled_descendants()

[Douglas Anderson <dianders@chromium.org>]

In (e583d9d USB: global suspend and remote wakeup don't mix) we
introduced wakeup_enabled_descendants() as a static function.  We'd
like to use this function in USB controller drivers to know if we
should keep the controller on during suspend time, since doing so has
a power impact.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
For relevant prior discussion of this idea, see:

https://lkml.kernel.org/r/1436207224-21849-4-git-send-email-dianders@chromium.org

If I'm reading all the responses correctly folks were of the opinion
that this patch is still the right way to go.

Changes in v2: None

 drivers/usb/core/hub.c  | 7 ++++---
 include/linux/usb/hcd.h | 5 +++++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 8d4631c81b9f..5e8f3fa7ae5a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3174,13 +3174,14 @@ static int usb_disable_remote_wakeup(struct usb_device *udev)
 }
 
 /* Count of wakeup-enabled devices at or below udev */
-static unsigned wakeup_enabled_descendants(struct usb_device *udev)
+unsigned usb_wakeup_enabled_descendants(struct usb_device *udev)
 {
 	struct usb_hub *hub = usb_hub_to_struct_hub(udev);
 
 	return udev->do_remote_wakeup +
 			(hub ? hub->wakeup_enabled_descendants : 0);
 }
+EXPORT_SYMBOL_GPL(usb_wakeup_enabled_descendants);
 
 /*
  * usb_port_suspend - suspend a usb device's upstream port
@@ -3282,7 +3283,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 	 * Therefore we will turn on the suspend feature if udev or any of its
 	 * descendants is enabled for remote wakeup.
 	 */
-	else if (PMSG_IS_AUTO(msg) || wakeup_enabled_descendants(udev) > 0)
+	else if (PMSG_IS_AUTO(msg) || usb_wakeup_enabled_descendants(udev) > 0)
 		status = set_port_feature(hub->hdev, port1,
 				USB_PORT_FEAT_SUSPEND);
 	else {
@@ -3687,7 +3688,7 @@ static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
 		}
 		if (udev)
 			hub->wakeup_enabled_descendants +=
-					wakeup_enabled_descendants(udev);
+					usb_wakeup_enabled_descendants(udev);
 	}
 
 	if (hdev->do_remote_wakeup && hub->quirk_check_port_auto_suspend) {
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 695931b03684..ed4fbbd1b35f 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -652,11 +652,16 @@ extern wait_queue_head_t usb_kill_urb_queue;
 #define usb_endpoint_out(ep_dir)	(!((ep_dir) & USB_DIR_IN))
 
 #ifdef CONFIG_PM
+extern unsigned usb_wakeup_enabled_descendants(struct usb_device *udev);
 extern void usb_root_hub_lost_power(struct usb_device *rhdev);
 extern int hcd_bus_suspend(struct usb_device *rhdev, pm_message_t msg);
 extern int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg);
 extern void usb_hcd_resume_root_hub(struct usb_hcd *hcd);
 #else
+static inline unsigned usb_wakeup_enabled_descendants(struct usb_device *udev)
+{
+	return 0;
+}
 static inline void usb_hcd_resume_root_hub(struct usb_hcd *hcd)
 {
 	return;
-- 
2.21.0.593.g511ec345e18-goog