[PATCH v3 1/2] Bluetooth: hci_ath: Add NULL check for tiocmget() and tiocmset() in ath_setup()

[Myungho Jung]

tiocmget() and tiocmset() operations are optional so they are not
guaranteed to be set. Return ENODEV in ath_setup() if tty driver doesn't
support the operations.

Fixes: 4c876c0edbdc ("hci_uart: Add Atheros support for address config")
Cc: <stable@xxxxxxxxxxxxxxx> # 4.1
Signed-off-by: Myungho Jung <mhjungk@xxxxxxxxx>
---
Changes in v2:
  - Add NULL check and return error in ath_setup() instead of
    ath_hci_uart_work()

Changes in v3:
  - Fix to return -ENODEV
  - Split into 2 patches
  - Add stable CC and fixes tags

 drivers/bluetooth/hci_ath.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c
index d568fbd94d6c..9f1ac1805d23 100644
--- a/drivers/bluetooth/hci_ath.c
+++ b/drivers/bluetooth/hci_ath.c
@@ -185,8 +185,14 @@ static int ath_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
 
 static int ath_setup(struct hci_uart *hu)
 {
+	struct tty_struct *tty = hu->tty;
+
 	BT_DBG("hu %p", hu);
 
+	/* tty driver should support operations to set RTS */
+	if (!tty->driver->ops->tiocmget || !tty->driver->ops->tiocmset)
+		return -ENODEV;
+
 	hu->hdev->set_bdaddr = ath_set_bdaddr;
 
 	return 0;
-- 
2.17.1