watchdog: imx2_wdt: Add power management support.

Add power management operations(suspend and resume) as part of
dev_pm_ops for IMX2 watchdog driver.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/imx2_wdt.c b/drivers/watchdog/imx2_wdt.c
index 65b84d8c0b93f0fb95c9c76ca9c183d77965a895..51d940beb3113cf8dada35b61d018beac5f92cb0 100644 (file)
--- a/drivers/watchdog/imx2_wdt.c
+++ b/drivers/watchdog/imx2_wdt.c
@@ -326,6 +326,52 @@ static void imx2_wdt_shutdown(struct platform_device *pdev)
        }
 }
 
+#ifdef CONFIG_PM_SLEEP
+/* Disable watchdog if it is active during suspend */
+static int imx2_wdt_suspend(struct device *dev)
+{
+       struct watchdog_device *wdog = dev_get_drvdata(dev);
+       struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+       imx2_wdt_set_timeout(wdog, IMX2_WDT_MAX_TIME);
+       imx2_wdt_ping(wdog);
+
+       /* Watchdog has been stopped but IP block is still running */
+       if (!watchdog_active(&wdog) && imx2_wdt_is_running(wdev))
+               del_timer_sync(&wdev->timer);
+
+       clk_disable_unprepare(wdev->clk);
+
+       return 0;
+}
+
+/* Enable watchdog and configure it if necessary */
+static int imx2_wdt_resume(struct device *dev)
+{
+       struct watchdog_device *wdog = dev_get_drvdata(dev);
+       struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+       clk_prepare_enable(wdev->clk);
+
+       if (watchdog_active(wdog) && !imx2_wdt_is_running(wdev)) {
+               /* Resumes from deep sleep we need restart
+                * the watchdog again.
+                */
+               imx2_wdt_setup(wdog);
+               imx2_wdt_set_timeout(wdog, wdog->timeout);
+               imx2_wdt_ping(wdog);
+       } else if (imx2_wdt_is_running(wdev)) {
+               imx2_wdt_ping(wdog);
+               mod_timer(&wdev->timer, jiffies + wdog->timeout * HZ / 2);
+       }
+
+       return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(imx2_wdt_pm_ops, imx2_wdt_suspend,
+                        imx2_wdt_resume);
+
 static const struct of_device_id imx2_wdt_dt_ids[] = {
        { .compatible = "fsl,imx21-wdt", },
        { /* sentinel */ }
@@ -337,6 +383,7 @@ static struct platform_driver imx2_wdt_driver = {
        .shutdown       = imx2_wdt_shutdown,
        .driver         = {
                .name   = DRIVER_NAME,
+               .pm     = &imx2_wdt_pm_ops,
                .of_match_table = imx2_wdt_dt_ids,
        },
 };