Commit eefadcbc authored Jan 25, 2018 by Uwe Kleine-König Committed by Greg Kroah-Hartman Feb 28, 2018

serial: altera: set RRDY flag also without irq

The UART can be operated without an irq. In this case a timer is setup
that regularily calls altera_uart_interrupt(). The receiving part
depends on pp->imr having the bit ALTERA_UART_STATUS_RRDY_MSK set,
otherwise altera_uart_rx_chars() is never called. So ensure that the bit
gets set (disguised as ALTERA_UART_CONTROL_RRDY_MSK) by not returning
early from altera_uart_startup() if port->irq is 0.

This doesn't affect the hardware as the ALTERA_UART_CONTROL_RRDY_MSK bit
isn't actually written to the control register.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 2ea6ad8b

drivers/tty/serial/altera_uart.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -321,13 +321,12 @@ static int altera_uart_startup(struct uart_port *port)
		{
		struct altera_uart *pp = container_of(port, struct altera_uart, port);
		unsigned long flags;
		int ret;

		if (!port->irq) {
		timer_setup(&pp->tmr, altera_uart_timer, 0);
		mod_timer(&pp->tmr, jiffies + uart_poll_timeout(port));
		return 0;
		}
		} else {
		int ret;

		ret = request_irq(port->irq, altera_uart_interrupt, 0,
		DRV_NAME, port);
		@@ -336,6 +335,7 @@ static int altera_uart_startup(struct uart_port *port)
		"interrupt vector=%d\n", port->line, port->irq);
		return ret;
		}
		}

		spin_lock_irqsave(&port->lock, flags);

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