watchdog: sama5d4: Implement resume hook

When resuming for the deepest state on sama5d2, it is necessary to restore
MR as the registers are lost.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
index 3230a842d015..f709962018ac 100644
--- a/drivers/watchdog/sama5d4_wdt.c
+++ b/drivers/watchdog/sama5d4_wdt.c
@@ -258,11 +258,28 @@ static const struct of_device_id sama5d4_wdt_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
 
+#ifdef CONFIG_PM_SLEEP
+static int sama5d4_wdt_resume(struct device *dev)
+{
+        struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
+
+        wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS);
+        if (wdt->mr & AT91_WDT_WDDIS)
+                wdt_write(wdt, AT91_WDT_MR, wdt->mr);
+
+        return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, NULL,
+                         sama5d4_wdt_resume);
+
 static struct platform_driver sama5d4_wdt_driver = {
         .probe          = sama5d4_wdt_probe,
         .remove         = sama5d4_wdt_remove,
         .driver         = {
                 .name   = "sama5d4_wdt",
+                .pm     = &sama5d4_wdt_pm_ops,
                 .of_match_table = sama5d4_wdt_of_match,
         }
 };