watchdog: renesas_wdt: Add suspend/resume support

On R-Car Gen2 and RZ/G1 the watchdog IP clock needs to be always ON,
on R-Car Gen3 we power the IP down during suspend.

This commit adds suspend/resume support, so that the watchdog counting
"pauses" during suspend on all of the SoCs compatible with this driver
and on those we are now adding support for (R-Car Gen2 and RZ/G1).

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 831ef83f6de15bce49cbb0839124f0c6cd1a7b60..024d54eda11e6acaaa8eb2ac821009a26a2cc35c 100644 (file)
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -49,6 +49,7 @@ struct rwdt_priv {
        void __iomem *base;
        struct watchdog_device wdev;
        unsigned long clk_rate;
+       u16 time_left;
        u8 cks;
 };
 
@@ -203,6 +204,30 @@ static int rwdt_remove(struct platform_device *pdev)
        return 0;
 }
 
+static int __maybe_unused rwdt_suspend(struct device *dev)
+{
+       struct rwdt_priv *priv = dev_get_drvdata(dev);
+
+       if (watchdog_active(&priv->wdev)) {
+               priv->time_left = readw(priv->base + RWTCNT);
+               rwdt_stop(&priv->wdev);
+       }
+       return 0;
+}
+
+static int __maybe_unused rwdt_resume(struct device *dev)
+{
+       struct rwdt_priv *priv = dev_get_drvdata(dev);
+
+       if (watchdog_active(&priv->wdev)) {
+               rwdt_start(&priv->wdev);
+               rwdt_write(priv, priv->time_left, RWTCNT);
+       }
+       return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(rwdt_pm_ops, rwdt_suspend, rwdt_resume);
+
 /*
  * This driver does also fit for R-Car Gen2 (r8a779[0-4]) WDT. However, for SMP
  * to work there, one also needs a RESET (RST) driver which does not exist yet
@@ -218,6 +243,7 @@ static struct platform_driver rwdt_driver = {
        .driver = {
                .name = "renesas_wdt",
                .of_match_table = rwdt_ids,
+               .pm = &rwdt_pm_ops,
        },
        .probe = rwdt_probe,
        .remove = rwdt_remove,