[PATCH v1] Bluetooth: btmtk: Fix failed to send func ctrl for MediaTek devices.

[Chris Lu <chris.lu@mediatek.com>]

Use usb_autopm_get_interface() and usb_autopm_put_interface()
in btmtk_usb_shutdown(), it could send func ctrl after enabling
autosuspend.

Bluetooth: btusb_mtk_hci_wmt_sync() hci0: Execution of wmt command
           timed out
Bluetooth: btusb_mtk_shutdown() hci0: Failed to send wmt func ctrl
           (-110)

Signed-off-by: Chris Lu <chris.lu@mediatek.com>
---
 drivers/bluetooth/btmtk.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 7fd9d5ddce02..224eafc27dbe 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -1472,10 +1472,15 @@ EXPORT_SYMBOL_GPL(btmtk_usb_setup);
 
 int btmtk_usb_shutdown(struct hci_dev *hdev)
 {
+	struct btmtk_data *data = hci_get_priv(hdev);
 	struct btmtk_hci_wmt_params wmt_params;
 	u8 param = 0;
 	int err;
 
+	err = usb_autopm_get_interface(data->intf);
+	if (err < 0)
+		return err;
+
 	/* Disable the device */
 	wmt_params.op = BTMTK_WMT_FUNC_CTRL;
 	wmt_params.flag = 0;
@@ -1486,9 +1491,11 @@ int btmtk_usb_shutdown(struct hci_dev *hdev)
 	err = btmtk_usb_hci_wmt_sync(hdev, &wmt_params);
 	if (err < 0) {
 		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
+		usb_autopm_put_interface(data->intf);
 		return err;
 	}
 
+	usb_autopm_put_interface(data->intf);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(btmtk_usb_shutdown);
-- 
2.45.2