Bluetooth: Add hook for driver to prevent wake from suspend

Let drivers have a hook to disable configuring scanning during suspend.
Drivers should use the device_may_wakeup function call to determine
whether hci should be configured for wakeup.

For example, an implementation for btusb may look like the following:

  bool btusb_prevent_wake(struct hci_dev *hdev)
  {
        struct btusb_data *data = hci_get_drvdata(hdev);
        return !device_may_wakeup(&data->udev->dev);
  }
Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Reviewed-by: Alain Michaud <alainm@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci_core.h

@@ -503,6 +503,7 @@ struct hci_dev {
 	int (*set_diag)(struct hci_dev *hdev, bool enable);
 	int (*set_bdaddr)(struct hci_dev *hdev, const bdaddr_t *bdaddr);
 	void (*cmd_timeout)(struct hci_dev *hdev);
+	bool (*prevent_wake)(struct hci_dev *hdev);
 };
 
 #define HCI_PHY_HANDLE(handle)	(handle & 0xff)

net/bluetooth/hci_core.c

@@ -3350,8 +3350,10 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
 		 */
 		ret = hci_change_suspend_state(hdev, BT_SUSPEND_DISCONNECT);
 
-		/* Only configure whitelist if disconnect succeeded */
-		if (!ret)
+		/* Only configure whitelist if disconnect succeeded and wake
+		 * isn't being prevented.
+		 */
+		if (!ret && !(hdev->prevent_wake && hdev->prevent_wake(hdev)))
 			ret = hci_change_suspend_state(hdev,
 						BT_SUSPEND_CONFIGURE_WAKE);
 	} else if (action == PM_POST_SUSPEND) {