From: Wolfram Sang <[email protected]>

Support an already running watchdog by checking its enable bit and set
up the status accordingly before registering the device.

Signed-off-by: Wolfram Sang <[email protected]>
---

Change since v1:

* removed custom code to handle RPM refcnt. The watchdog core does it
  already.

Tested again on a Renesas Salvator-XS (R-Car M3N) with and without the
'open_timeout' command line parameter.

After all these discussions, the patch became quite simple again :/
Still, thanks for all the discussions to make sure we didn't overlook
clock handling.

 drivers/watchdog/renesas_wdt.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 00662a8e039c..47fce4de0110 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -194,6 +194,7 @@ static int rwdt_probe(struct platform_device *pdev)
        struct clk *clk;
        unsigned long clks_per_sec;
        int ret, i;
+       u8 csra;
 
        if (rwdt_blacklisted(dev))
                return -ENODEV;
@@ -213,8 +214,8 @@ static int rwdt_probe(struct platform_device *pdev)
        pm_runtime_enable(dev);
        pm_runtime_get_sync(dev);
        priv->clk_rate = clk_get_rate(clk);
-       priv->wdev.bootstatus = (readb_relaxed(priv->base + RWTCSRA) &
-                               RWTCSRA_WOVF) ? WDIOF_CARDRESET : 0;
+       csra = readb_relaxed(priv->base + RWTCSRA);
+       priv->wdev.bootstatus = csra & RWTCSRA_WOVF ? WDIOF_CARDRESET : 0;
        pm_runtime_put(dev);
 
        if (!priv->clk_rate) {
@@ -252,6 +253,13 @@ static int rwdt_probe(struct platform_device *pdev)
        /* This overrides the default timeout only if DT configuration was 
found */
        watchdog_init_timeout(&priv->wdev, 0, dev);
 
+       /* Check if FW enabled the watchdog */
+       if (csra & RWTCSRA_TME) {
+               /* Ensure properly initialized dividers */
+               rwdt_start(&priv->wdev);
+               set_bit(WDOG_HW_RUNNING, &priv->wdev.status);
+       }
+
        ret = watchdog_register_device(&priv->wdev);
        if (ret < 0)
                goto out_pm_disable;
-- 
2.20.1

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