linux-kernel - [PATCH 2/2] watchdog: gpio_wdt: add "start-at-boot" feature

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Date:   Wed, 21 Apr 2021 18:26:21 +0200
From:   Francesco Zanella <francesco.zanella@...ar.com>
To:     linux-watchdog@...r.kernel.org, wim@...ux-watchdog.org,
        linux@...ck-us.net
Cc:     devicetree@...r.kernel.org, robh+dt@...nel.org,
        linux-kernel@...r.kernel.org,
        Francesco Zanella <francesco.zanella@...ar.com>
Subject: [PATCH 2/2] watchdog: gpio_wdt: add "start-at-boot" feature

If "start-at-boot" property is present in the device tree, start pinging
hw watchdog at probe, in order to take advantage of kernel configs:
- WATCHDOG_HANDLE_BOOT_ENABLED: Avoid possible reboot if hw watchdog was
  been enabled before the kernel (by uboot for example) and userspace
  doesn't take control of /dev/watchdog in time;
- WATCHDOG_OPEN_TIMEOUT: Reboot if userspace doesn't take control of
  /dev/watchdog within the timeout.

Signed-off-by: Francesco Zanella <francesco.zanella@...ar.com>
---
 drivers/watchdog/gpio_wdt.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c
index 0923201ce874..1e6f0322ab7a 100644
--- a/drivers/watchdog/gpio_wdt.c
+++ b/drivers/watchdog/gpio_wdt.c
@@ -31,6 +31,7 @@ struct gpio_wdt_priv {
 	struct gpio_desc	*gpiod;
 	bool			state;
 	bool			always_running;
+	bool			start_at_boot;
 	unsigned int		hw_algo;
 	struct watchdog_device	wdd;
 };
@@ -147,6 +148,9 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 	priv->always_running = of_property_read_bool(np,
 						     "always-running");
 
+	priv->start_at_boot = of_property_read_bool(np,
+						    "start-at-boot");
+
 	watchdog_set_drvdata(&priv->wdd, priv);
 
 	priv->wdd.info		= &gpio_wdt_ident;
@@ -161,7 +165,7 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 
 	watchdog_stop_on_reboot(&priv->wdd);
 
-	if (priv->always_running)
+	if (priv->always_running || priv->start_at_boot)
 		gpio_wdt_start(&priv->wdd);
 
 	return devm_watchdog_register_device(dev, &priv->wdd);
-- 
2.17.1