From e1c609efbc0333840f2af2d875ca52ed8ee18587 Mon Sep 17 00:00:00 2001
From: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Date: Fri, 14 Mar 2008 14:54:13 +0100
Subject: [PATCH] atmel_serial: Drain console TX shifter before suspending

Funny things may happen if we stop the USART clock before the shifter is
empty. Prevent this from happening by waiting until the shifter is
completely drained before allowing suspend to continue.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
---
 drivers/serial/atmel_serial.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 5f0414fc1b106..6aeef22bd2039 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -1454,6 +1454,12 @@ static int atmel_serial_suspend(struct platform_device *pdev,
 	struct uart_port *port = platform_get_drvdata(pdev);
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
+	if (atmel_is_console_port(port) && console_suspend_enabled) {
+		/* Drain the TX shifter */
+		while (!(UART_GET_CSR(port) & ATMEL_US_TXEMPTY))
+			cpu_relax();
+	}
+
 	if (device_may_wakeup(&pdev->dev)
 	    && !atmel_serial_clk_will_stop())
 		enable_irq_wake(port->irq);
-- 
2.30.2