watchdog: gpio_wdt: Add option for early registration

In some situation, mainly when it's not possible to disable a
watchdog, you may want the watchdog driver to be started as soon
as possible.

Adding GPIO_WATCHDOG_ARCH_INITCALL to raise initcall from
module_init to arch_initcall.

This patch require watchdog registration deferral mechanism
Signed-off-by: NJean-Baptiste Theou <jtheou@adeneo-embedded.us>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>

drivers/watchdog/Kconfig

+
 #
 # Watchdog device configuration
 #
@@ -113,6 +114,17 @@ config GPIO_WATCHDOG
 	  If you say yes here you get support for watchdog device
 	  controlled through GPIO-line.
 
+config GPIO_WATCHDOG_ARCH_INITCALL
+	bool "Register the watchdog as early as possible"
+	depends on GPIO_WATCHDOG=y
+	help
+	  In some situations, the default initcall level (module_init)
+	  in not early enough in the boot process to avoid the watchdog
+	  to be triggered.
+	  If you say yes here, the initcall level would be raised to
+	  arch_initcall.
+	  If in doubt, say N.
+
 config MENF21BMC_WATCHDOG
 	tristate "MEN 14F021P00 BMC Watchdog"
 	depends on MFD_MENF21BMC

drivers/watchdog/gpio_wdt.c

@@ -267,7 +267,16 @@ static struct platform_driver gpio_wdt_driver = {
 	.probe	= gpio_wdt_probe,
 	.remove	= gpio_wdt_remove,
 };
+
+#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
+static int __init gpio_wdt_init(void)
+{
+	return platform_driver_register(&gpio_wdt_driver);
+}
+arch_initcall(gpio_wdt_init);
+#else
 module_platform_driver(gpio_wdt_driver);
+#endif
 
 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 MODULE_DESCRIPTION("GPIO Watchdog");