Bluetooth: btusb: add shutdown function for wcn6855

we should send hci reset command before bt turn off, which can reset bt
firmware status.
Signed-off-by: Tim Jiang <tjiang@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btusb.c

@@ -4260,6 +4260,20 @@ static bool btusb_prevent_wake(struct hci_dev *hdev)
 	return !device_may_wakeup(&data->udev->dev);
 }
 
+static int btusb_shutdown_qca(struct hci_dev *hdev)
+{
+	struct sk_buff *skb;
+
+	skb = __hci_cmd_sync(hdev, HCI_OP_RESET, 0, NULL, HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		bt_dev_err(hdev, "HCI reset during shutdown failed");
+		return PTR_ERR(skb);
+	}
+	kfree_skb(skb);
+
+	return 0;
+}
+
 static int btusb_probe(struct usb_interface *intf,
 		       const struct usb_device_id *id)
 {
@@ -4519,6 +4533,7 @@ static int btusb_probe(struct usb_interface *intf,
 
 	if (id->driver_info & BTUSB_QCA_WCN6855) {
 		data->setup_on_usb = btusb_setup_qca;
+		hdev->shutdown = btusb_shutdown_qca;
 		hdev->set_bdaddr = btusb_set_bdaddr_wcn6855;
 		hdev->cmd_timeout = btusb_qca_cmd_timeout;
 		set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);