linux-kernel - [PATCHv3 2/5] driver: serial: omap: prevent runtime PM for "no_console

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Date:	Wed, 24 Apr 2013 18:45:50 +0530
From:	Sourav Poddar <sourav.poddar@...com>
To:	<gregkh@...uxfoundation.org>, <tony@...mide.com>,
	<rmk+kernel@....linux.org.uk>, <khilman@...aro.org>
CC:	<linux-serial@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>,
	Sourav Poddar <sourav.poddar@...com>
Subject: [PATCHv3 2/5] driver: serial: omap: prevent runtime PM for "no_console_suspend"

The driver manages "no_console_suspend" by preventing runtime PM
during the suspend path, which forces the console UART to stay awake.

Signed-off-by: Sourav Poddar <sourav.poddar@...com>
---
 drivers/tty/serial/omap-serial.c |   29 ++++++++++++++++++++++++++++-
 1 files changed, 28 insertions(+), 1 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 08332f3..468e7ad 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -161,6 +161,7 @@ struct uart_omap_port {
 	u32			calc_latency;
 	struct work_struct	qos_work;
 	struct pinctrl		*pins;
+	bool			is_suspending;
 };
 
 #define to_uart_omap_port(p)	((container_of((p), struct uart_omap_port, port)))
@@ -1278,6 +1279,24 @@ static struct uart_driver serial_omap_reg = {
 };
 
 #ifdef CONFIG_PM_SLEEP
+static int serial_omap_prepare(struct device *dev)
+{
+	struct uart_omap_port *up = dev_get_drvdata(dev);
+
+	if (!console_suspend_enabled && uart_console(&up->port))
+		up->is_suspending = true;
+
+	return 0;
+}
+
+static void serial_omap_complete(struct device *dev)
+{
+	struct uart_omap_port *up = dev_get_drvdata(dev);
+
+	if (!console_suspend_enabled && uart_console(&up->port))
+		up->is_suspending = false;
+}
+
 static int serial_omap_suspend(struct device *dev)
 {
 	struct uart_omap_port *up = dev_get_drvdata(dev);
@@ -1296,7 +1315,10 @@ static int serial_omap_resume(struct device *dev)
 
 	return 0;
 }
-#endif
+#else
+#define serial_omap_prepare NULL
+#define serial_omap_prepare NULL
+#endif /* CONFIG_PM_SLEEP */
 
 static void omap_serial_fill_features_erratas(struct uart_omap_port *up)
 {
@@ -1582,6 +1604,9 @@ static int serial_omap_runtime_suspend(struct device *dev)
 	struct uart_omap_port *up = dev_get_drvdata(dev);
 	struct omap_uart_port_info *pdata = dev->platform_data;
 
+	if (up->is_suspending)
+		return -EBUSY;
+
 	if (!up)
 		return -EINVAL;
 
@@ -1632,6 +1657,8 @@ static const struct dev_pm_ops serial_omap_dev_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(serial_omap_suspend, serial_omap_resume)
 	SET_RUNTIME_PM_OPS(serial_omap_runtime_suspend,
 				serial_omap_runtime_resume, NULL)
+	.prepare        = serial_omap_prepare,
+	.complete       = serial_omap_complete,
 };
 
 #if defined(CONFIG_OF)
-- 
1.7.1

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