linux-kernel - [PATCH 2/3] watchdog: da9063: Use pre configured timeout when watchdog is running

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Date:   Thu, 26 Mar 2020 16:02:02 +0100
From:   Stefan Riedmueller <s.riedmueller@...tec.de>
To:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Support Opensource <support.opensource@...semi.com>
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] watchdog: da9063: Use pre configured timeout when watchdog is running

If the watchdog is already running during probe use its pre-configured
timeout instead of a default timeout to make sure the watchdog is pinged
in time until userspace takes over.

Signed-off-by: Stefan Riedmueller <s.riedmueller@...tec.de>
---
 drivers/watchdog/da9063_wdt.c | 29 ++++++++++++++++++-----------
 1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
index 3d65e92a4e3f..34d0c4f03814 100644
--- a/drivers/watchdog/da9063_wdt.c
+++ b/drivers/watchdog/da9063_wdt.c
@@ -46,15 +46,16 @@ static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
 }
 
 /*
- * Return 0 if watchdog is disabled, else non zero.
+ * Read the currently active timeout.
+ * Zero means the watchdog is disabled.
  */
-static unsigned int da9063_wdt_is_running(struct da9063 *da9063)
+static unsigned int da9063_wdt_read_timeout(struct da9063 *da9063)
 {
 	unsigned int val;
 
 	regmap_read(da9063->regmap, DA9063_REG_CONTROL_D, &val);
 
-	return val & DA9063_TWDSCALE_MASK;
+	return wdt_timeout[val & DA9063_TWDSCALE_MASK];
 }
 
 static int da9063_wdt_disable_timer(struct da9063 *da9063)
@@ -191,6 +192,7 @@ static int da9063_wdt_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct da9063 *da9063;
 	struct watchdog_device *wdd;
+	int timeout;
 
 	if (!dev->parent)
 		return -EINVAL;
@@ -214,15 +216,20 @@ static int da9063_wdt_probe(struct platform_device *pdev)
 	watchdog_set_restart_priority(wdd, 128);
 	watchdog_set_drvdata(wdd, da9063);
 
-	/* Set default timeout, maybe override it with DT value, scale it */
-	wdd->timeout = DA9063_WDG_TIMEOUT;
-	watchdog_init_timeout(wdd, 0, dev);
-	da9063_wdt_set_timeout(wdd, wdd->timeout);
-
-	/* Change the timeout to the default value if the watchdog is running */
-	if (da9063_wdt_is_running(da9063)) {
-		da9063_wdt_update_timeout(da9063, wdd->timeout);
+	/*
+	 * Use pre-configured timeout if watchdog is already running.
+	 * Otherwise set default timeout, maybe override it with DT value,
+	 * scale it
+	 */
+	timeout = da9063_wdt_read_timeout(da9063);
+	if (timeout) {
+		wdd->timeout = timeout;
 		set_bit(WDOG_HW_RUNNING, &wdd->status);
+		dev_info(da9063->dev, "watchdog is running (%u s)", timeout);
+	} else {
+		wdd->timeout = DA9063_WDG_TIMEOUT;
+		watchdog_init_timeout(wdd, 0, dev);
+		da9063_wdt_set_timeout(wdd, wdd->timeout);
 	}
 
 	return devm_watchdog_register_device(dev, wdd);
-- 
2.23.0