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

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Date:   Thu, 16 Feb 2017 20:30:53 +0100
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     Wim Van Sebroeck <wim@...ana.be>,
        Nicolas Ferre <nicolas.ferre@...el.com>,
        linux-watchdog@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Subject: [PATCH v2 3/3] 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@...e-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