[PATCHv5 2/2] driver: serial: omap: prevent runtime PM for "no_console_suspend"

From: Sourav Poddar
Date: Fri Apr 26 2013 - 16:05:23 EST


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@xxxxxx>
Reviewed-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/tty/serial/omap-serial.c | 34 +++++++++++++++++++++++++++++++++-
1 files changed, 33 insertions(+), 1 deletions(-)

diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 30d4f7a..9457fe3 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)))
@@ -1312,6 +1313,22 @@ 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);
+
+ up->is_suspending = true;
+
+ return 0;
+}
+
+static void serial_omap_complete(struct device *dev)
+{
+ struct uart_omap_port *up = dev_get_drvdata(dev);
+
+ up->is_suspending = false;
+}
+
static int serial_omap_suspend(struct device *dev)
{
struct uart_omap_port *up = dev_get_drvdata(dev);
@@ -1330,7 +1347,10 @@ 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)
{
@@ -1616,6 +1636,16 @@ 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;

+ /*
+ * When using 'no_console_suspend', the console UART must not be
+ * suspended. Since driver suspend is managed by runtime suspend,
+ * preventing runtime suspend (by returning error) will keep device
+ * active during suspend.
+ */
+ if (up->is_suspending && !console_suspend_enabled &&
+ uart_console(&up->port))
+ return -EBUSY;
+
if (!up)
return -EINVAL;

@@ -1666,6 +1696,8 @@ 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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