linux-kernel - [PATCH] watchdog: omap_wdt: Add 'early

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Date:	Tue,  9 Sep 2014 15:07:37 +0200
From:	Rostislav Lisovy <lisovy@...il.com>
To:	Wim Van Sebroeck <wim@...ana.be>, linux-watchdog@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc:	sojkam1@....cvut.cz, michal.vokac@...ap.cz, lisovy@...il.com,
	Rostislav Lisovy <lisovy@...ica.cz>
Subject: [PATCH] watchdog: omap_wdt: Add 'early_disable' module parameter

This parameter makes it possible to control if the watchdog
is being disabled during initialization or will stay enabled
in case it was previously initialized in the bootloader.

To maintain the existing behavior, the default value is 'true',
thus the watchdog is disabled during initialization.

This new feature is highly inspired by the w83627hf_wdt.c

Signed-off-by: Rostislav Lisovy <lisovy@...ica.cz>
---
 drivers/watchdog/omap_wdt.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/omap_wdt.c b/drivers/watchdog/omap_wdt.c
index 3691b15..8f4cabe 100644
--- a/drivers/watchdog/omap_wdt.c
+++ b/drivers/watchdog/omap_wdt.c
@@ -53,6 +53,10 @@ static unsigned timer_margin;
 module_param(timer_margin, uint, 0);
 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
 
+static bool early_disable = true;
+module_param(early_disable, bool, 0);
+MODULE_PARM_DESC(early_disable, "Disable watchdog at boot time (default=1)");
+
 struct omap_wdt_dev {
 	void __iomem    *base;          /* physical */
 	struct device   *dev;
@@ -255,7 +259,15 @@ static int omap_wdt_probe(struct platform_device *pdev)
 	omap_wdt->bootstatus = (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT)) ?
 				WDIOF_CARDRESET : 0;
 
-	omap_wdt_disable(wdev);
+	if (early_disable) {
+		pr_warn("Stopping previously enabled watchdog until userland kicks in\n");
+		omap_wdt_disable(wdev);
+	} else {
+		pr_info("Watchdog already running. Resetting timeout to %d sec\n",
+			omap_wdt->timeout);
+		omap_wdt_set_timeout(omap_wdt, omap_wdt->timeout);
+		omap_wdt_ping(omap_wdt);
+	}
 
 	ret = watchdog_register_device(omap_wdt);
 	if (ret) {
@@ -267,7 +279,8 @@ static int omap_wdt_probe(struct platform_device *pdev)
 		readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
 		omap_wdt->timeout);
 
-	pm_runtime_put_sync(wdev->dev);
+	if (early_disable)
+		pm_runtime_put_sync(wdev->dev);
 
 	return 0;
 }
-- 
1.9.1

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