linux-kernel - [PATCH v2 2/2] watchdog: dw: save/restore control and timeout across suspend/resume

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Date:   Fri,  9 Mar 2018 19:46:07 -0800
From:   Brian Norris <briannorris@...omium.org>
To:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     <linux-kernel@...r.kernel.org>, linux-watchdog@...r.kernel.org,
        Doug Anderson <dianders@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        <linux-rockchip@...ts.infradead.org>,
        Brian Norris <briannorris@...omium.org>
Subject: [PATCH v2 2/2] watchdog: dw: save/restore control and timeout across suspend/resume

Some platforms lose this state in suspend. It should be safe to do this
unconditionally.

Signed-off-by: Brian Norris <briannorris@...omium.org>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
---
v2: no change
---
 drivers/watchdog/dw_wdt.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 918357bccf5e..501aebb5b81f 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -57,6 +57,9 @@ struct dw_wdt {
 	unsigned long		rate;
 	struct watchdog_device	wdd;
 	struct reset_control	*rst;
+	/* Save/restore */
+	u32			control;
+	u32			timeout;
 };
 
 #define to_dw_wdt(wdd)	container_of(wdd, struct dw_wdt, wdd)
@@ -205,6 +208,9 @@ static int dw_wdt_suspend(struct device *dev)
 {
 	struct dw_wdt *dw_wdt = dev_get_drvdata(dev);
 
+	dw_wdt->control = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+	dw_wdt->timeout = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
+
 	clk_disable_unprepare(dw_wdt->clk);
 
 	return 0;
@@ -218,6 +224,9 @@ static int dw_wdt_resume(struct device *dev)
 	if (err)
 		return err;
 
+	writel(dw_wdt->timeout, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
+	writel(dw_wdt->control, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
+
 	dw_wdt_ping(&dw_wdt->wdd);
 
 	return 0;
-- 
2.16.2.660.g709887971b-goog