linux-kernel - [PATCH 1/3] watchdog: da9062: Use pre-configured timeout until userspace takes over

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Message-Id: <20200326150203.371673-1-s.riedmueller@phytec.de>
Date:   Thu, 26 Mar 2020 16:02:01 +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 1/3] watchdog: da9062: Use pre-configured timeout until userspace takes over

If the watchdog is already running during probe read back its
pre-configured timeout (set e.g. by the bootloader) and use it to ping
the watchdog until userspace takes over. Otherwise the default timeout
set before might not result in a fast enough ping.

Signed-off-by: Stefan Riedmueller <s.riedmueller@...tec.de>
---
 drivers/watchdog/da9062_wdt.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
index 0ad15d55071c..6d81b1276b87 100644
--- a/drivers/watchdog/da9062_wdt.c
+++ b/drivers/watchdog/da9062_wdt.c
@@ -35,6 +35,14 @@ struct da9062_watchdog {
 	bool use_sw_pm;
 };
 
+static unsigned int da9062_wdt_read_timeout(struct da9062_watchdog *wdt)
+{
+	int val;
+
+	regmap_read(wdt->hw->regmap, DA9062AA_CONTROL_D, &val);
+	return wdt_timeout[val & DA9062AA_TWDSCALE_MASK];
+}
+
 static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
 {
 	unsigned int i;
@@ -184,6 +192,7 @@ static int da9062_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	int ret;
+	int timeout;
 	struct da9062 *chip;
 	struct da9062_watchdog *wdt;
 
@@ -213,6 +222,13 @@ static int da9062_wdt_probe(struct platform_device *pdev)
 	watchdog_set_drvdata(&wdt->wdtdev, wdt);
 	dev_set_drvdata(dev, &wdt->wdtdev);
 
+	timeout = da9062_wdt_read_timeout(wdt);
+	if (timeout > 0) {
+		wdt->wdtdev.timeout = timeout;
+		set_bit(WDOG_HW_RUNNING, &wdt->wdtdev.status);
+		dev_info(wdt->hw->dev, "watchdog is running (%u s)", timeout);
+	}
+
 	ret = devm_watchdog_register_device(dev, &wdt->wdtdev);
 	if (ret < 0)
 		return ret;
-- 
2.23.0