BTMTKUART_TX_WAIT_VND_EVT
set_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
err = wait_on_bit_timeout(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT,
clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
if (test_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state)) {
if (test_and_clear_bit(BTMTKUART_TX_WAIT_VND_EVT,
wake_up_bit(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT);