serial: of-serial: add PM suspend/resume support

This adds PM suspend/resume support for the of-serial driver
to provide power management support on devices attatched to it.

Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 27981e2b9430..8bc2563335ae 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -240,6 +240,32 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
         return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int of_serial_suspend(struct device *dev)
+{
+        struct of_serial_info *info = dev_get_drvdata(dev);
+
+        serial8250_suspend_port(info->line);
+        if (info->clk)
+                clk_disable_unprepare(info->clk);
+
+        return 0;
+}
+
+static int of_serial_resume(struct device *dev)
+{
+        struct of_serial_info *info = dev_get_drvdata(dev);
+
+        if (info->clk)
+                clk_prepare_enable(info->clk);
+
+        serial8250_resume_port(info->line);
+
+        return 0;
+}
+#endif
+static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
+
 /*
  * A few common types, add more as needed.
  */
@@ -271,6 +297,7 @@ static struct platform_driver of_platform_serial_driver = {
                 .name = "of_serial",
                 .owner = THIS_MODULE,
                 .of_match_table = of_platform_serial_table,
+                .pm = &of_serial_pm_ops,
         },
         .probe = of_platform_serial_probe,
         .remove = of_platform_serial_remove,