[PATCH v2 3/3] watchdog: sama5d4: Implement resume hook

[Alexandre Belloni]

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.bell...@free-electrons.com>
---
Changes in v2:
 - cache mr beofre suspending

 drivers/watchdog/sama5d4_wdt.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
index 2a60251806d2..5ddeb4803dc3 100644
--- a/drivers/watchdog/sama5d4_wdt.c
+++ b/drivers/watchdog/sama5d4_wdt.c
@@ -28,6 +28,7 @@
 struct sama5d4_wdt {
        struct watchdog_device  wdd;
        void __iomem            *reg_base;
+       u32                     mr;
 };
 
 static int wdt_timeout = WDT_DEFAULT_TIMEOUT;
@@ -248,11 +249,42 @@ 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_suspend(struct device *dev)
+{
+       struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
+
+       wdt->mr = wdt_read(wdt, AT91_WDT_MR);
+
+       return 0;
+}
+
+static int sama5d4_wdt_resume(struct device *dev)
+{
+       struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
+       u32 reg;
+
+       reg = wdt_read(wdt, AT91_WDT_MR);
+       if (reg & AT91_WDT_WDDIS)
+               wdt_write(wdt, AT91_WDT_MR, reg & ~AT91_WDT_WDDIS);
+
+       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, sama5d4_wdt_suspend,
+                        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,
        }
 };
-- 
2.11.0