1 files changed, 36 insertions, 22 deletions

diff --git a/drivers/tty/serial/altera_uart.c b/drivers/tty/serial/altera_uart.c
index b88b05f8e81e..0e487ce091ac 100644
--- a/drivers/tty/serial/altera_uart.c
+++ b/drivers/tty/serial/altera_uart.c
@@ -109,6 +109,20 @@ static unsigned int altera_uart_get_mctrl(struct uart_port *port)
 	return sigs;
 }
 
+static void altera_uart_update_ctrl_reg(struct altera_uart *pp)
+{
+	unsigned short imr = pp->imr;
+
+	/*
+	 * If the device doesn't have an irq, ensure that the irq bits are
+	 * masked out to keep the irq line inactive.
+	 */
+	if (!pp->port.irq)
+		imr &= ALTERA_UART_CONTROL_TRBK_MSK | ALTERA_UART_CONTROL_RTS_MSK;
+
+	altera_uart_writel(&pp->port, imr, ALTERA_UART_CONTROL_REG);
+}
+
 static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
 {
 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
@@ -118,7 +132,7 @@ static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
 		pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
 	else
 		pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
-	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
+	altera_uart_update_ctrl_reg(pp);
 }
 
 static void altera_uart_start_tx(struct uart_port *port)
@@ -126,7 +140,7 @@ static void altera_uart_start_tx(struct uart_port *port)
 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
 
 	pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
-	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
+	altera_uart_update_ctrl_reg(pp);
 }
 
 static void altera_uart_stop_tx(struct uart_port *port)
@@ -134,7 +148,7 @@ static void altera_uart_stop_tx(struct uart_port *port)
 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
 
 	pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
-	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
+	altera_uart_update_ctrl_reg(pp);
 }
 
 static void altera_uart_stop_rx(struct uart_port *port)
@@ -142,7 +156,7 @@ static void altera_uart_stop_rx(struct uart_port *port)
 	struct altera_uart *pp = container_of(port, struct altera_uart, port);
 
 	pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
-	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
+	altera_uart_update_ctrl_reg(pp);
 }
 
 static void altera_uart_break_ctl(struct uart_port *port, int break_state)
@@ -155,7 +169,7 @@ static void altera_uart_break_ctl(struct uart_port *port, int break_state)
 		pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
 	else
 		pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
-	altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
+	altera_uart_update_ctrl_reg(pp);
 	spin_unlock_irqrestore(&port->lock, flags);
 }
 
@@ -262,7 +276,7 @@ static void altera_uart_tx_chars(struct altera_uart *pp)
 
 	if (xmit->head == xmit->tail) {
 		pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
-		altera_uart_writel(port, pp->imr, ALTERA_UART_CONTROL_REG);
+		altera_uart_update_ctrl_reg(pp);
 	}
 }
 
@@ -307,27 +321,27 @@ 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;
-	}
-
-	ret = request_irq(port->irq, altera_uart_interrupt, 0,
-			DRV_NAME, port);
-	if (ret) {
-		pr_err(DRV_NAME ": unable to attach Altera UART %d "
-		       "interrupt vector=%d\n", port->line, port->irq);
-		return ret;
+	} else {
+		int ret;
+
+		ret = request_irq(port->irq, altera_uart_interrupt, 0,
+				DRV_NAME, port);
+		if (ret) {
+			pr_err(DRV_NAME ": unable to attach Altera UART %d "
+			       "interrupt vector=%d\n", port->line, port->irq);
+			return ret;
+		}
 	}
 
 	spin_lock_irqsave(&port->lock, flags);
 
 	/* Enable RX interrupts now */
 	pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
-	writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
+	altera_uart_update_ctrl_reg(pp);
 
 	spin_unlock_irqrestore(&port->lock, flags);
 
@@ -343,7 +357,7 @@ static void altera_uart_shutdown(struct uart_port *port)
 
 	/* Disable all interrupts now */
 	pp->imr = 0;
-	writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
+	altera_uart_update_ctrl_reg(pp);
 
 	spin_unlock_irqrestore(&port->lock, flags);
 
@@ -432,7 +446,7 @@ static void altera_uart_console_putc(struct uart_port *port, int c)
 		 ALTERA_UART_STATUS_TRDY_MSK))
 		cpu_relax();
 
-	writel(c, port->membase + ALTERA_UART_TXDATA_REG);
+	altera_uart_writel(port, c, ALTERA_UART_TXDATA_REG);
 }
 
 static void altera_uart_console_write(struct console *co, const char *s,
@@ -502,13 +516,13 @@ static int __init altera_uart_earlycon_setup(struct earlycon_device *dev,
 		return -ENODEV;
 
 	/* Enable RX interrupts now */
-	writel(ALTERA_UART_CONTROL_RRDY_MSK,
-	       port->membase + ALTERA_UART_CONTROL_REG);
+	altera_uart_writel(port, ALTERA_UART_CONTROL_RRDY_MSK,
+			   ALTERA_UART_CONTROL_REG);
 
 	if (dev->baud) {
 		unsigned int baudclk = port->uartclk / dev->baud;
 
-		writel(baudclk, port->membase + ALTERA_UART_DIVISOR_REG);
+		altera_uart_writel(port, baudclk, ALTERA_UART_DIVISOR_REG);
 	}
 
 	dev->con->write = altera_uart_earlycon_write;