UART_TX_IRQ
if (!mvuart->irq[UART_TX_IRQ]) {
ret = devm_request_irq(port->dev, mvuart->irq[UART_TX_IRQ],
mvuart->irq[UART_TX_IRQ]);
if (!mvuart->irq[UART_TX_IRQ]) {
devm_free_irq(port->dev, mvuart->irq[UART_TX_IRQ], port);
mvuart->irq[UART_TX_IRQ] = irq;