Merge git://www.linux-watchdog.org/linux-watchdog

Pull watchdog updates from Wim Van Sebroeck:

 - Add Renesas RZ/A WDT Watchdog driver

 - STM32 Independent WatchDoG (IWDG) support

 - UniPhier watchdog support

 - Add F71868 support

 - Add support for NCT6793D and NCT6795D

 - dw_wdt: add reset lines support

 - core: add option to avoid early handling of watchdog

 - core: introduce watchdog_worker_should_ping helper

 - Cleanups and improvements for sama5d4, intel-mid_wdt, s3c2410_wdt,
   orion_wdt, gpio_wdt, it87_wdt, meson_wdt, davinci_wdt, bcm47xx_wdt,
   zx2967_wdt, cadence_wdt

* git://www.linux-watchdog.org/linux-watchdog: (32 commits)
  watchdog: introduce watchdog_worker_should_ping helper
  watchdog: uniphier: add UniPhier watchdog driver
  dt-bindings: watchdog: add description for UniPhier WDT controller
  watchdog: cadence_wdt: make of_device_ids const.
  watchdog: zx2967: constify zx2967_wdt_ops.
  watchdog: bcm47xx_wdt: constify bcm47xx_wdt_hard_ops and bcm47xx_wdt_soft_ops
  watchdog: davinci: Add missing clk_disable_unprepare().
  watchdog: davinci: Handle return value of clk_prepare_enable
  watchdog: meson: Handle return value of clk_prepare_enable
  watchdog: it87: Add support for various Super-IO chips
  watchdog: it87: Use infrastructure to stop watchdog on reboot
  watchdog: it87: Drop support for resetting watchdog though CIR and Game port
  watchdog: it87: Convert to use watchdog core infrastructure
  watchdog: it87: Drop FSF mailing address
  watchdog: dw_wdt: get reset lines from dt
  watchdog: bindings: dw_wdt: add reset lines
  watchdog: w83627hf: Add support for NCT6793D and NCT6795D
  watchdog: core: add option to avoid early handling of watchdog
  watchdog: f71808e_wdt: Add F71868 support
  watchdog: Add STM32 IWDG driver
  ...

Documentation/devicetree/bindings/watchdog/da9062-wdt.txt

+* Dialog Semiconductor DA9062/61 Watchdog Timer
+
+Required properties:
+
+- compatible: should be one of the following valid compatible string lines:
+	"dlg,da9061-watchdog", "dlg,da9062-watchdog"
+	"dlg,da9062-watchdog"
+
+Example: DA9062
+
+	pmic0: da9062@58 {
+		watchdog {
+			compatible = "dlg,da9062-watchdog";
+		};
+	};
+
+Example: DA9061 using a fall-back compatible for the DA9062 watchdog driver
+
+	pmic0: da9061@58 {
+		watchdog {
+			compatible = "dlg,da9061-watchdog", "dlg,da9062-watchdog";
+		};
+	};

Documentation/devicetree/bindings/watchdog/dw_wdt.txt

@@ -10,6 +10,8 @@ Required Properties:
 Optional Properties:
 
 - interrupts	: The interrupt used for the watchdog timeout warning.
+- resets	: phandle pointing to the system reset controller with
+		line index for the watchdog.
 
 Example:
 
@@ -18,4 +20,5 @@ Example:
 		reg = <0xffd02000 0x1000>;
 		interrupts = <0 171 4>;
 		clocks = <&per_base_clk>;
+		resets = <&rst WDT0_RESET>;
 	};

Documentation/devicetree/bindings/watchdog/renesas-wdt.txt

@@ -2,10 +2,11 @@ Renesas Watchdog Timer (WDT) Controller
 
 Required properties:
 - compatible : Should be "renesas,<soctype>-wdt", and
-	       "renesas,rcar-gen3-wdt" as fallback.
+	       "renesas,rcar-gen3-wdt" or "renesas,rza-wdt" as fallback.
 	       Examples with soctypes are:
 	         - "renesas,r8a7795-wdt" (R-Car H3)
 	         - "renesas,r8a7796-wdt" (R-Car M3-W)
+	         - "renesas,r7s72100-wdt" (RZ/A1)
 
   When compatible with the generic version, nodes must list the SoC-specific
   version corresponding to the platform first, followed by the generic
@@ -17,6 +18,7 @@ Required properties:
 Optional properties:
 - timeout-sec : Contains the watchdog timeout in seconds
 - power-domains : the power domain the WDT belongs to
+- interrupts: Some WDTs have an interrupt when used in interval timer mode
 
 Examples:
 

Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt

+STM32 Independent WatchDoG (IWDG)
+---------------------------------
+
+Required properties:
+- compatible: "st,stm32-iwdg"
+- reg: physical base address and length of the registers set for the device
+- clocks: must contain a single entry describing the clock input
+
+Optional Properties:
+- timeout-sec: Watchdog timeout value in seconds.
+
+Example:
+
+iwdg: watchdog@40003000 {
+	compatible = "st,stm32-iwdg";
+	reg = <0x40003000 0x400>;
+	clocks = <&clk_lsi>;
+	timeout-sec = <32>;
+};

Documentation/devicetree/bindings/watchdog/uniphier-wdt.txt

+UniPhier watchdog timer controller
+
+This UniPhier watchdog timer controller must be under sysctrl node.
+
+Required properties:
+- compatible: should be "socionext,uniphier-wdt"
+
+Example:
+
+	sysctrl@61840000 {
+		compatible = "socionext,uniphier-ld11-sysctrl",
+			     "simple-mfd", "syscon";
+		reg = <0x61840000 0x4000>;
+
+		watchdog {
+			compatible = "socionext,uniphier-wdt";
+		}
+
+		other nodes ...
+	};

Documentation/watchdog/watchdog-parameters.txt

@@ -369,6 +369,12 @@ timeout: Watchdog timeout in seconds. (0<timeout<N, default=60)
 nowayout: Watchdog cannot be stopped once started
 	(default=kernel config parameter)
 -------------------------------------------------
+uniphier_wdt:
+timeout: Watchdog timeout in power of two seconds.
+	(1 <= timeout <= 128, default=64)
+nowayout: Watchdog cannot be stopped once started
+	(default=kernel config parameter)
+-------------------------------------------------
 w83627hf_wdt:
 wdt_io: w83627hf/thf WDT io port (default 0x2E)
 timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.

drivers/watchdog/Kconfig

@@ -46,6 +46,17 @@ config WATCHDOG_NOWAYOUT
 	  get killed. If you say Y here, the watchdog cannot be stopped once
 	  it has been started.
 
+config WATCHDOG_HANDLE_BOOT_ENABLED
+	bool "Update boot-enabled watchdog until userspace takes over"
+	default y
+	help
+	  The default watchdog behaviour (which you get if you say Y here) is
+	  to ping watchdog devices that were enabled before the driver has
+	  been loaded until control is taken over from userspace using the
+	  /dev/watchdog file. If you say N here, the kernel will not update
+	  the watchdog on its own. Thus if your userspace does not start fast
+	  enough your device will reboot.
+
 config WATCHDOG_SYSFS
 	bool "Read different watchdog information through sysfs"
 	help
@@ -721,6 +732,14 @@ config RENESAS_WDT
 	  This driver adds watchdog support for the integrated watchdogs in the
 	  Renesas R-Car and other SH-Mobile SoCs (usually named RWDT or SWDT).
 
+config RENESAS_RZAWDT
+	tristate "Renesas RZ/A WDT Watchdog"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	select WATCHDOG_CORE
+	help
+	  This driver adds watchdog support for the integrated watchdogs in the
+	  Renesas RZ/A SoCs. These watchdogs can be used to reset a system.
+
 config ASPEED_WATCHDOG
 	tristate "Aspeed 2400 watchdog support"
 	depends on ARCH_ASPEED || COMPILE_TEST
@@ -744,6 +763,30 @@ config ZX2967_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called zx2967_wdt.
 
+config STM32_WATCHDOG
+	tristate "STM32 Independent WatchDoG (IWDG) support"
+	depends on ARCH_STM32
+	select WATCHDOG_CORE
+	default y
+	help
+	  Say Y here to include support for the watchdog timer
+	  in stm32 SoCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stm32_iwdg.
+
+config UNIPHIER_WATCHDOG
+	tristate "UniPhier watchdog support"
+	depends on ARCH_UNIPHIER || COMPILE_TEST
+	depends on OF && MFD_SYSCON
+	select WATCHDOG_CORE
+	help
+	  Say Y here to include support watchdog timer embedded
+	  into the UniPhier system.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called uniphier_wdt.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
@@ -829,11 +872,12 @@ config EBC_C384_WDT
 	  the timeout module parameter.
 
 config F71808E_WDT
-	tristate "Fintek F71808E, F71862FG, F71869, F71882FG and F71889FG Watchdog"
+	tristate "Fintek F718xx, F818xx Super I/O Watchdog"
 	depends on X86
 	help
-	  This is the driver for the hardware watchdog on the Fintek
-	  F71808E, F71862FG, F71869, F71882FG and F71889FG Super I/O controllers.
+	  This is the driver for the hardware watchdog on the Fintek F71808E,
+	  F71862FG, F71868, F71869, F71882FG, F71889FG, F81865 and F81866
+	  Super I/O controllers.
 
 	  You can compile this driver directly into the kernel, or use
 	  it as a module.  The module will be called f71808e_wdt.
@@ -1037,13 +1081,12 @@ config IT8712F_WDT
 config IT87_WDT
 	tristate "IT87 Watchdog Timer"
 	depends on X86
+	select WATCHDOG_CORE
 	---help---
-	  This is the driver for the hardware watchdog on the ITE IT8620,
-	  IT8702, IT8712, IT8716, IT8718, IT8720, IT8721, IT8726 and IT8728
-	  Super I/O chips.
-
-	  If the driver does not work, then make sure that the game port in
-	  the BIOS is enabled.
+	  This is the driver for the hardware watchdog on the ITE IT8607,
+	  IT8620, IT8622, IT8625, IT8628, IT8655, IT8665, IT8686, IT8702,
+	  IT8712, IT8716, IT8718, IT8720, IT8721, IT8726, IT8728, and
+	  IT8783 Super I/O chips.
 
 	  This watchdog simply watches your kernel to make sure it doesn't
 	  freeze, and if it does, it reboots your computer after a certain

drivers/watchdog/Makefile

@@ -82,8 +82,11 @@ obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
 obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
 obj-$(CONFIG_ATLAS7_WATCHDOG) += atlas7_wdt.o
 obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
+obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
 obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
 obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o
+obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
+obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

drivers/watchdog/bcm47xx_wdt.c

@@ -97,7 +97,7 @@ static int bcm47xx_wdt_restart(struct watchdog_device *wdd,
 	return 0;
 }
 
-static struct watchdog_ops bcm47xx_wdt_hard_ops = {
+static const struct watchdog_ops bcm47xx_wdt_hard_ops = {
 	.owner		= THIS_MODULE,
 	.start		= bcm47xx_wdt_hard_start,
 	.stop		= bcm47xx_wdt_hard_stop,
@@ -168,7 +168,7 @@ static const struct watchdog_info bcm47xx_wdt_info = {
 				WDIOF_MAGICCLOSE,
 };
 
-static struct watchdog_ops bcm47xx_wdt_soft_ops = {
+static const struct watchdog_ops bcm47xx_wdt_soft_ops = {
 	.owner		= THIS_MODULE,
 	.start		= bcm47xx_wdt_soft_start,
 	.stop		= bcm47xx_wdt_soft_stop,

drivers/watchdog/cadence_wdt.c

@@ -458,7 +458,7 @@ static int __maybe_unused cdns_wdt_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(cdns_wdt_pm_ops, cdns_wdt_suspend, cdns_wdt_resume);
 
-static struct of_device_id cdns_wdt_of_match[] = {
+static const struct of_device_id cdns_wdt_of_match[] = {
 	{ .compatible = "cdns,wdt-r1p2", },
 	{ /* end of table */ }
 };

drivers/watchdog/davinci_wdt.c

@@ -173,7 +173,11 @@ static int davinci_wdt_probe(struct platform_device *pdev)
 		return PTR_ERR(davinci_wdt->clk);
 	}
 
-	clk_prepare_enable(davinci_wdt->clk);
+	ret = clk_prepare_enable(davinci_wdt->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to prepare clock\n");
+		return ret;
+	}
 
 	platform_set_drvdata(pdev, davinci_wdt);
 
@@ -198,8 +202,10 @@ static int davinci_wdt_probe(struct platform_device *pdev)
 		return PTR_ERR(davinci_wdt->base);
 
 	ret = watchdog_register_device(wdd);
-	if (ret < 0)
+	if (ret < 0) {
+		clk_disable_unprepare(davinci_wdt->clk);
 		dev_err(dev, "cannot register watchdog device\n");
+	}
 
 	return ret;
 }

drivers/watchdog/dw_wdt.c

@@ -29,6 +29,7 @@
 #include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/watchdog.h>
 
 #define WDOG_CONTROL_REG_OFFSET		    0x00
@@ -54,6 +55,7 @@ struct dw_wdt {
 	struct clk		*clk;
 	unsigned long		rate;
 	struct watchdog_device	wdd;
+	struct reset_control	*rst;
 };
 
 #define to_dw_wdt(wdd)	container_of(wdd, struct dw_wdt, wdd)
@@ -234,6 +236,14 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
 		goto out_disable_clk;
 	}
 
+	dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+	if (IS_ERR(dw_wdt->rst)) {
+		ret = PTR_ERR(dw_wdt->rst);
+		goto out_disable_clk;
+	}
+
+	reset_control_deassert(dw_wdt->rst);
+
 	wdd = &dw_wdt->wdd;
 	wdd->info = &dw_wdt_ident;
 	wdd->ops = &dw_wdt_ops;
@@ -279,6 +289,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev)
 	struct dw_wdt *dw_wdt = platform_get_drvdata(pdev);
 
 	watchdog_unregister_device(&dw_wdt->wdd);
+	reset_control_assert(dw_wdt->rst);
 	clk_disable_unprepare(dw_wdt->clk);
 
 	return 0;

drivers/watchdog/f71808e_wdt.c

@@ -57,6 +57,7 @@
 #define SIO_F71808_ID		0x0901	/* Chipset ID */
 #define SIO_F71858_ID		0x0507	/* Chipset ID */
 #define SIO_F71862_ID		0x0601	/* Chipset ID */
+#define SIO_F71868_ID		0x1106	/* Chipset ID */
 #define SIO_F71869_ID		0x0814	/* Chipset ID */
 #define SIO_F71869A_ID		0x1007	/* Chipset ID */
 #define SIO_F71882_ID		0x0541	/* Chipset ID */
@@ -101,7 +102,7 @@ MODULE_PARM_DESC(timeout,
 static unsigned int pulse_width = WATCHDOG_PULSE_WIDTH;
 module_param(pulse_width, uint, 0);
 MODULE_PARM_DESC(pulse_width,
-	"Watchdog signal pulse width. 0(=level), 1 ms, 25 ms, 125 ms or 5000 ms"
+	"Watchdog signal pulse width. 0(=level), 1, 25, 30, 125, 150, 5000 or 6000 ms"
 			" (default=" __MODULE_STRING(WATCHDOG_PULSE_WIDTH) ")");
 
 static unsigned int f71862fg_pin = WATCHDOG_F71862FG_PIN;
@@ -119,13 +120,14 @@ module_param(start_withtimeout, uint, 0);
 MODULE_PARM_DESC(start_withtimeout, "Start watchdog timer on module load with"
 	" given initial timeout. Zero (default) disables this feature.");
 
-enum chips { f71808fg, f71858fg, f71862fg, f71869, f71882fg, f71889fg, f81865,
-	     f81866};
+enum chips { f71808fg, f71858fg, f71862fg, f71868, f71869, f71882fg, f71889fg,
+	     f81865, f81866};
 
 static const char *f71808e_names[] = {
 	"f71808fg",
 	"f71858fg",
 	"f71862fg",
+	"f71868",
 	"f71869",
 	"f71882fg",
 	"f71889fg",
@@ -252,16 +254,23 @@ static int watchdog_set_timeout(int timeout)
 static int watchdog_set_pulse_width(unsigned int pw)
 {
 	int err = 0;
+	unsigned int t1 = 25, t2 = 125, t3 = 5000;
+
+	if (watchdog.type == f71868) {
+		t1 = 30;
+		t2 = 150;
+		t3 = 6000;
+	}
 
 	mutex_lock(&watchdog.lock);
 
-	if        (pw <=    1) {
+	if        (pw <=  1) {
 		watchdog.pulse_val = 0;
-	} else if (pw <=   25) {
+	} else if (pw <= t1) {
 		watchdog.pulse_val = 1;
-	} else if (pw <=  125) {
+	} else if (pw <= t2) {
 		watchdog.pulse_val = 2;
-	} else if (pw <= 5000) {
+	} else if (pw <= t3) {
 		watchdog.pulse_val = 3;
 	} else {
 		pr_err("pulse width out of range\n");
@@ -354,6 +363,7 @@ static int watchdog_start(void)
 			goto exit_superio;
 		break;
 
+	case f71868:
 	case f71869:
 		/* GPIO14 --> WDTRST# */
 		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 4);
@@ -792,6 +802,9 @@ static int __init f71808e_find(int sioaddr)
 		watchdog.type = f71862fg;
 		err = f71862fg_pin_configure(0); /* validate module parameter */
 		break;
+	case SIO_F71868_ID:
+		watchdog.type = f71868;
+		break;
 	case SIO_F71869_ID:
 	case SIO_F71869A_ID:
 		watchdog.type = f71869;

drivers/watchdog/gpio_wdt.c

@@ -18,7 +18,6 @@
 
 #define SOFT_TIMEOUT_MIN	1
 #define SOFT_TIMEOUT_DEF	60
-#define SOFT_TIMEOUT_MAX	0xffff
 
 enum {
 	HW_ALGO_TOGGLE,
@@ -30,11 +29,7 @@ struct gpio_wdt_priv {
 	bool			active_low;
 	bool			state;
 	bool			always_running;
-	bool			armed;
 	unsigned int		hw_algo;
-	unsigned int		hw_margin;
-	unsigned long		last_jiffies;
-	struct timer_list	timer;
 	struct watchdog_device	wdd;
 };
 
@@ -47,21 +42,10 @@ static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
 		gpio_direction_input(priv->gpio);
 }
 
-static void gpio_wdt_hwping(unsigned long data)
+static int gpio_wdt_ping(struct watchdog_device *wdd)
 {
-	struct watchdog_device *wdd = (struct watchdog_device *)data;
 	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	if (priv->armed && time_after(jiffies, priv->last_jiffies +
-				      msecs_to_jiffies(wdd->timeout * 1000))) {
-		dev_crit(wdd->parent,
-			 "Timer expired. System will reboot soon!\n");
-		return;
-	}
-
-	/* Restart timer */
-	mod_timer(&priv->timer, jiffies + priv->hw_margin);
-
 	switch (priv->hw_algo) {
 	case HW_ALGO_TOGGLE:
 		/* Toggle output pin */
@@ -75,55 +59,33 @@ static void gpio_wdt_hwping(unsigned long data)
 		gpio_set_value_cansleep(priv->gpio, priv->active_low);
 		break;
 	}
-}
-
-static void gpio_wdt_start_impl(struct gpio_wdt_priv *priv)
-{
-	priv->state = priv->active_low;
-	gpio_direction_output(priv->gpio, priv->state);
-	priv->last_jiffies = jiffies;
-	gpio_wdt_hwping((unsigned long)&priv->wdd);
+	return 0;
 }
 
 static int gpio_wdt_start(struct watchdog_device *wdd)
 {
 	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	gpio_wdt_start_impl(priv);
-	priv->armed = true;
+	priv->state = priv->active_low;
+	gpio_direction_output(priv->gpio, priv->state);
 
-	return 0;
+	set_bit(WDOG_HW_RUNNING, &wdd->status);
+
+	return gpio_wdt_ping(wdd);
 }
 
 static int gpio_wdt_stop(struct watchdog_device *wdd)
 {
 	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
 
-	priv->armed = false;
 	if (!priv->always_running) {
-		mod_timer(&priv->timer, 0);
 		gpio_wdt_disable(priv);
+		clear_bit(WDOG_HW_RUNNING, &wdd->status);
 	}
 
 	return 0;
 }
 
-static int gpio_wdt_ping(struct watchdog_device *wdd)
-{
-	struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
-
-	priv->last_jiffies = jiffies;
-
-	return 0;
-}
-
-static int gpio_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
-{
-	wdd->timeout = t;
-
-	return gpio_wdt_ping(wdd);
-}
-
 static const struct watchdog_info gpio_wdt_ident = {
 	.options	= WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
 			  WDIOF_SETTIMEOUT,
@@ -135,7 +97,6 @@ static const struct watchdog_ops gpio_wdt_ops = {
 	.start		= gpio_wdt_start,
 	.stop		= gpio_wdt_stop,
 	.ping		= gpio_wdt_ping,
-	.set_timeout	= gpio_wdt_set_timeout,
 };
 
 static int gpio_wdt_probe(struct platform_device *pdev)
@@ -185,9 +146,6 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 	if (hw_margin < 2 || hw_margin > 65535)
 		return -EINVAL;
 
-	/* Use safe value (1/2 of real timeout) */
-	priv->hw_margin = msecs_to_jiffies(hw_margin / 2);
-
 	priv->always_running = of_property_read_bool(pdev->dev.of_node,
 						     "always-running");
 
@@ -196,31 +154,26 @@ static int gpio_wdt_probe(struct platform_device *pdev)
 	priv->wdd.info		= &gpio_wdt_ident;
 	priv->wdd.ops		= &gpio_wdt_ops;
 	priv->wdd.min_timeout	= SOFT_TIMEOUT_MIN;
-	priv->wdd.max_timeout	= SOFT_TIMEOUT_MAX;
+	priv->wdd.max_hw_heartbeat_ms = hw_margin;
 	priv->wdd.parent	= &pdev->dev;
 
 	if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0)
 		priv->wdd.timeout = SOFT_TIMEOUT_DEF;
 
-	setup_timer(&priv->timer, gpio_wdt_hwping, (unsigned long)&priv->wdd);
-
 	watchdog_stop_on_reboot(&priv->wdd);
 
-	ret = watchdog_register_device(&priv->wdd);
-	if (ret)
-		return ret;
-
 	if (priv->always_running)
-		gpio_wdt_start_impl(priv);
+		gpio_wdt_start(&priv->wdd);
 
-	return 0;
+	ret = watchdog_register_device(&priv->wdd);
+
+	return ret;
 }
 
 static int gpio_wdt_remove(struct platform_device *pdev)
 {
 	struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
 
-	del_timer_sync(&priv->timer);
 	watchdog_unregister_device(&priv->wdd);
 
 	return 0;

drivers/watchdog/intel-mid_wdt.c

@@ -147,8 +147,21 @@ static int mid_wdt_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	/* Make sure the watchdog is not running */
-	wdt_stop(wdt_dev);
+	/*
+	 * The firmware followed by U-Boot leaves the watchdog running
+	 * with the default threshold which may vary. When we get here
+	 * we should make a decision to prevent any side effects before
+	 * user space daemon will take care of it. The best option,
+	 * taking into consideration that there is no way to read values
+	 * back from hardware, is to enforce watchdog being run with
+	 * deterministic values.
+	 */
+	ret = wdt_start(wdt_dev);
+	if (ret)
+		return ret;
+
+	/* Make sure the watchdog is serviced */
+	set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
 
 	ret = devm_watchdog_register_device(&pdev->dev, wdt_dev);
 	if (ret) {

drivers/watchdog/meson_gxbb_wdt.c

@@ -203,7 +203,9 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(data->clk))
 		return PTR_ERR(data->clk);
 
-	clk_prepare_enable(data->clk);
+	ret = clk_prepare_enable(data->clk);
+	if (ret)
+		return ret;
 
 	platform_set_drvdata(pdev, data);
 

drivers/watchdog/orion_wdt.c

@@ -651,5 +651,5 @@ module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("platform:orion_wdt");

drivers/watchdog/rza_wdt.c

+/*
+ * Renesas RZ/A Series WDT Driver
+ *
+ * Copyright (C) 2017 Renesas Electronics America, Inc.
+ * Copyright (C) 2017 Chris Brandt
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_TIMEOUT		30
+
+/* Watchdog Timer Registers */
+#define WTCSR			0
+#define WTCSR_MAGIC		0xA500
+#define WTSCR_WT		BIT(6)
+#define WTSCR_TME		BIT(5)
+#define WTSCR_CKS(i)		(i)
+
+#define WTCNT			2
+#define WTCNT_MAGIC		0x5A00
+
+#define WRCSR			4
+#define WRCSR_MAGIC		0x5A00
+#define WRCSR_RSTE		BIT(6)
+#define WRCSR_CLEAR_WOVF	0xA500	/* special value */
+
+struct rza_wdt {
+	struct watchdog_device wdev;
+	void __iomem *base;
+	struct clk *clk;
+};
+
+static int rza_wdt_start(struct watchdog_device *wdev)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	/* Stop timer */
+	writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
+
+	/* Must dummy read WRCSR:WOVF at least once before clearing */
+	readb(priv->base + WRCSR);
+	writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
+
+	/*
+	 * Start timer with slowest clock source and reset option enabled.
+	 */
+	writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
+	writew(WTCNT_MAGIC | 0, priv->base + WTCNT);
+	writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME | WTSCR_CKS(7),
+	       priv->base + WTCSR);
+
+	return 0;
+}
+
+static int rza_wdt_stop(struct watchdog_device *wdev)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
+
+	return 0;
+}
+
+static int rza_wdt_ping(struct watchdog_device *wdev)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	writew(WTCNT_MAGIC | 0, priv->base + WTCNT);
+
+	return 0;
+}
+
+static int rza_wdt_restart(struct watchdog_device *wdev, unsigned long action,
+			    void *data)
+{
+	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
+
+	/* Stop timer */
+	writew(WTCSR_MAGIC | 0, priv->base + WTCSR);
+
+	/* Must dummy read WRCSR:WOVF at least once before clearing */
+	readb(priv->base + WRCSR);
+	writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
+
+	/*
+	 * Start timer with fastest clock source and only 1 clock left before
+	 * overflow with reset option enabled.
+	 */
+	writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
+	writew(WTCNT_MAGIC | 255, priv->base + WTCNT);
+	writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME, priv->base + WTCSR);
+
+	/*
+	 * Actually make sure the above sequence hits hardware before sleeping.
+	 */
+	wmb();
+
+	/* Wait for WDT overflow (reset) */
+	udelay(20);
+
+	return 0;
+}
+
+static const struct watchdog_info rza_wdt_ident = {
+	.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+	.identity = "Renesas RZ/A WDT Watchdog",
+};
+
+static const struct watchdog_ops rza_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = rza_wdt_start,
+	.stop = rza_wdt_stop,
+	.ping = rza_wdt_ping,
+	.restart = rza_wdt_restart,
+};
+
+static int rza_wdt_probe(struct platform_device *pdev)
+{
+	struct rza_wdt *priv;
+	struct resource *res;
+	unsigned long rate;
+	int ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk))
+		return PTR_ERR(priv->clk);
+
+	rate = clk_get_rate(priv->clk);
+	if (rate < 16384) {
+		dev_err(&pdev->dev, "invalid clock rate (%ld)\n", rate);
+		return -ENOENT;
+	}
+
+	/* Assume slowest clock rate possible (CKS=7) */
+	rate /= 16384;
+
+	priv->wdev.info = &rza_wdt_ident,
+	priv->wdev.ops = &rza_wdt_ops,
+	priv->wdev.parent = &pdev->dev;
+
+	/*
+	 * Since the max possible timeout of our 8-bit count register is less
+	 * than a second, we must use max_hw_heartbeat_ms.
+	 */
+	priv->wdev.max_hw_heartbeat_ms = (1000 * U8_MAX) / rate;
+	dev_dbg(&pdev->dev, "max hw timeout of %dms\n",
+		 priv->wdev.max_hw_heartbeat_ms);
+
+	priv->wdev.min_timeout = 1;
+	priv->wdev.timeout = DEFAULT_TIMEOUT;
+
+	watchdog_init_timeout(&priv->wdev, 0, &pdev->dev);
+	watchdog_set_drvdata(&priv->wdev, priv);
+
+	ret = devm_watchdog_register_device(&pdev->dev, &priv->wdev);
+	if (ret)
+		dev_err(&pdev->dev, "Cannot register watchdog device\n");
+
+	return ret;
+}
+
+static const struct of_device_id rza_wdt_of_match[] = {
+	{ .compatible = "renesas,rza-wdt", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rza_wdt_of_match);
+
+static struct platform_driver rza_wdt_driver = {
+	.probe = rza_wdt_probe,
+	.driver = {
+		.name = "rza_wdt",
+		.of_match_table = rza_wdt_of_match,
+	},
+};
+
+module_platform_driver(rza_wdt_driver);
+
+MODULE_DESCRIPTION("Renesas RZ/A WDT Driver");
+MODULE_AUTHOR("Chris Brandt <chris.brandt@renesas.com>");
+MODULE_LICENSE("GPL v2");

drivers/watchdog/s3c2410_wdt.c

-/* linux/drivers/char/watchdog/s3c2410_wdt.c
- *
+/*
  * Copyright (c) 2004 Simtec Electronics
  *	Ben Dooks <ben@simtec.co.uk>
  *
@@ -17,11 +16,7 @@
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-*/
+ */
 
 #include <linux/module.h>
 #include <linux/moduleparam.h>
@@ -37,6 +32,7 @@
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>
 #include <linux/delay.h>
@@ -94,8 +90,7 @@ MODULE_PARM_DESC(tmr_atboot,
 			__MODULE_STRING(S3C2410_WATCHDOG_ATBOOT));
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
-MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, "
-			"0 to reboot (default 0)");
+MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default 0)");
 
 /**
  * struct s3c2410_wdt_variant - Per-variant config data
@@ -131,7 +126,7 @@ struct s3c2410_wdt {
 	unsigned long		wtdat_save;
 	struct watchdog_device	wdt_device;
 	struct notifier_block	freq_transition;
-	struct s3c2410_wdt_variant *drv_data;
+	const struct s3c2410_wdt_variant *drv_data;
 	struct regmap *pmureg;
 };
 
@@ -310,7 +305,8 @@ static inline int s3c2410wdt_is_running(struct s3c2410_wdt *wdt)
 	return readl(wdt->reg_base + S3C2410_WTCON) & S3C2410_WTCON_ENABLE;
 }
 
-static int s3c2410wdt_set_heartbeat(struct watchdog_device *wdd, unsigned timeout)
+static int s3c2410wdt_set_heartbeat(struct watchdog_device *wdd,
+				    unsigned int timeout)
 {
 	struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd);
 	unsigned long freq = clk_get_rate(wdt->clock);
@@ -401,7 +397,7 @@ static const struct watchdog_ops s3c2410wdt_ops = {
 	.restart = s3c2410wdt_restart,
 };
 
-static struct watchdog_device s3c2410_wdd = {
+static const struct watchdog_device s3c2410_wdd = {
 	.info = &s3c2410_wdt_ident,
 	.ops = &s3c2410wdt_ops,
 	.timeout = S3C2410_WATCHDOG_DEFAULT_TIME,
@@ -507,22 +503,24 @@ static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
 	return 0;
 }
 
-static inline struct s3c2410_wdt_variant *
+static inline const struct s3c2410_wdt_variant *
 s3c2410_get_wdt_drv_data(struct platform_device *pdev)
 {
-	if (pdev->dev.of_node) {
-		const struct of_device_id *match;
-		match = of_match_node(s3c2410_wdt_match, pdev->dev.of_node);
-		return (struct s3c2410_wdt_variant *)match->data;
-	} else {
-		return (struct s3c2410_wdt_variant *)
-			platform_get_device_id(pdev)->driver_data;
+	const struct s3c2410_wdt_variant *variant;
+
+	variant = of_device_get_match_data(&pdev->dev);
+	if (!variant) {
+		/* Device matched by platform_device_id */
+		variant = (struct s3c2410_wdt_variant *)
+			   platform_get_device_id(pdev)->driver_data;
 	}
+
+	return variant;
 }
 
 static int s3c2410wdt_probe(struct platform_device *pdev)
 {
-	struct device *dev;
+	struct device *dev = &pdev->dev;
 	struct s3c2410_wdt *wdt;
 	struct resource *wdt_mem;
 	struct resource *wdt_irq;
@@ -530,13 +528,11 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
 	int started = 0;
 	int ret;
 
-	dev = &pdev->dev;
-
 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 	if (!wdt)
 		return -ENOMEM;
 
-	wdt->dev = &pdev->dev;
+	wdt->dev = dev;
 	spin_lock_init(&wdt->lock);
 	wdt->wdt_device = s3c2410_wdd;
 
@@ -592,7 +588,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
 	/* see if we can actually set the requested timer margin, and if
 	 * not, try the default value */
 
-	watchdog_init_timeout(&wdt->wdt_device, tmr_margin, &pdev->dev);
+	watchdog_init_timeout(&wdt->wdt_device, tmr_margin, dev);
 	ret = s3c2410wdt_set_heartbeat(&wdt->wdt_device,
 					wdt->wdt_device.timeout);
 	if (ret) {
@@ -601,11 +597,10 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
 
 		if (started == 0)
 			dev_info(dev,
-			   "tmr_margin value out of range, default %d used\n",
-			       S3C2410_WATCHDOG_DEFAULT_TIME);
+				 "tmr_margin value out of range, default %d used\n",
+				 S3C2410_WATCHDOG_DEFAULT_TIME);
 		else
-			dev_info(dev, "default timer value is out of range, "
-							"cannot start\n");
+			dev_info(dev, "default timer value is out of range, cannot start\n");
 	}
 
 	ret = devm_request_irq(dev, wdt_irq->start, s3c2410wdt_irq, 0,
@@ -619,7 +614,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
 	watchdog_set_restart_priority(&wdt->wdt_device, 128);
 
 	wdt->wdt_device.bootstatus = s3c2410wdt_get_bootstatus(wdt);
-	wdt->wdt_device.parent = &pdev->dev;
+	wdt->wdt_device.parent = dev;
 
 	ret = watchdog_register_device(&wdt->wdt_device);
 	if (ret) {
@@ -754,7 +749,6 @@ static struct platform_driver s3c2410wdt_driver = {
 
 module_platform_driver(s3c2410wdt_driver);
 
-MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
-	      "Dimitry Andric <dimitry.andric@tomtom.com>");
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, Dimitry Andric <dimitry.andric@tomtom.com>");
 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
 MODULE_LICENSE("GPL");

drivers/watchdog/sama5d4_wdt.c

@@ -228,15 +228,13 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
 
 	wdt->reg_base = regs;
 
-	if (pdev->dev.of_node) {
-		irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
-		if (!irq)
-			dev_warn(&pdev->dev, "failed to get IRQ from DT\n");
+	irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
+	if (!irq)
+		dev_warn(&pdev->dev, "failed to get IRQ from DT\n");
 
-		ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt);
-		if (ret)
-			return ret;
-	}
+	ret = of_sama5d4_wdt_init(pdev->dev.of_node, wdt);
+	if (ret)
+		return ret;
 
 	if ((wdt->mr & AT91_WDT_WDFIEN) && irq) {
 		ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler,
@@ -302,6 +300,11 @@ static int sama5d4_wdt_resume(struct device *dev)
 {
 	struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
 
+	/*
+	 * FIXME: writing MR also pings the watchdog which may not be desired.
+	 * This should only be done when the registers are lost on suspend but
+	 * there is no way to get this information right now.
+	 */
 	sama5d4_wdt_init(wdt);
 
 	return 0;

drivers/watchdog/stm32_iwdg.c

+/*
+ * Driver for STM32 Independent Watchdog
+ *
+ * Copyright (C) Yannick Fertre 2017
+ * Author: Yannick Fertre <yannick.fertre@st.com>
+ *
+ * This driver is based on tegra_wdt.c
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+/* IWDG registers */
+#define IWDG_KR		0x00 /* Key register */
+#define IWDG_PR		0x04 /* Prescaler Register */
+#define IWDG_RLR	0x08 /* ReLoad Register */
+#define IWDG_SR		0x0C /* Status Register */
+#define IWDG_WINR	0x10 /* Windows Register */
+
+/* IWDG_KR register bit mask */
+#define KR_KEY_RELOAD	0xAAAA /* reload counter enable */
+#define KR_KEY_ENABLE	0xCCCC /* peripheral enable */
+#define KR_KEY_EWA	0x5555 /* write access enable */
+#define KR_KEY_DWA	0x0000 /* write access disable */
+
+/* IWDG_PR register bit values */
+#define PR_4		0x00 /* prescaler set to 4 */
+#define PR_8		0x01 /* prescaler set to 8 */
+#define PR_16		0x02 /* prescaler set to 16 */
+#define PR_32		0x03 /* prescaler set to 32 */
+#define PR_64		0x04 /* prescaler set to 64 */
+#define PR_128		0x05 /* prescaler set to 128 */
+#define PR_256		0x06 /* prescaler set to 256 */
+
+/* IWDG_RLR register values */
+#define RLR_MIN		0x07C /* min value supported by reload register */
+#define RLR_MAX		0xFFF /* max value supported by reload register */
+
+/* IWDG_SR register bit mask */
+#define FLAG_PVU	BIT(0) /* Watchdog prescaler value update */
+#define FLAG_RVU	BIT(1) /* Watchdog counter reload value update */
+
+/* set timeout to 100000 us */
+#define TIMEOUT_US	100000
+#define SLEEP_US	1000
+
+struct stm32_iwdg {
+	struct watchdog_device	wdd;
+	void __iomem		*regs;
+	struct clk		*clk;
+	unsigned int		rate;
+};
+
+static inline u32 reg_read(void __iomem *base, u32 reg)
+{
+	return readl_relaxed(base + reg);
+}
+
+static inline void reg_write(void __iomem *base, u32 reg, u32 val)
+{
+	writel_relaxed(val, base + reg);
+}
+
+static int stm32_iwdg_start(struct watchdog_device *wdd)
+{
+	struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+	u32 val = FLAG_PVU | FLAG_RVU;
+	u32 reload;
+	int ret;
+
+	dev_dbg(wdd->parent, "%s\n", __func__);
+
+	/* prescaler fixed to 256 */
+	reload = clamp_t(unsigned int, ((wdd->timeout * wdt->rate) / 256) - 1,
+			 RLR_MIN, RLR_MAX);
+
+	/* enable write access */
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_EWA);
+
+	/* set prescaler & reload registers */
+	reg_write(wdt->regs, IWDG_PR, PR_256); /* prescaler fix to 256 */
+	reg_write(wdt->regs, IWDG_RLR, reload);
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_ENABLE);
+
+	/* wait for the registers to be updated (max 100ms) */
+	ret = readl_relaxed_poll_timeout(wdt->regs + IWDG_SR, val,
+					 !(val & (FLAG_PVU | FLAG_RVU)),
+					 SLEEP_US, TIMEOUT_US);
+	if (ret) {
+		dev_err(wdd->parent,
+			"Fail to set prescaler or reload registers\n");
+		return ret;
+	}
+
+	/* reload watchdog */
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
+
+	return 0;
+}
+
+static int stm32_iwdg_ping(struct watchdog_device *wdd)
+{
+	struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+
+	dev_dbg(wdd->parent, "%s\n", __func__);
+
+	/* reload watchdog */
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
+
+	return 0;
+}
+
+static int stm32_iwdg_set_timeout(struct watchdog_device *wdd,
+				  unsigned int timeout)
+{
+	dev_dbg(wdd->parent, "%s timeout: %d sec\n", __func__, timeout);
+
+	wdd->timeout = timeout;
+
+	if (watchdog_active(wdd))
+		return stm32_iwdg_start(wdd);
+
+	return 0;
+}
+
+static const struct watchdog_info stm32_iwdg_info = {
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_MAGICCLOSE |
+			  WDIOF_KEEPALIVEPING,
+	.identity	= "STM32 Independent Watchdog",
+};
+
+static struct watchdog_ops stm32_iwdg_ops = {
+	.owner		= THIS_MODULE,
+	.start		= stm32_iwdg_start,
+	.ping		= stm32_iwdg_ping,
+	.set_timeout	= stm32_iwdg_set_timeout,
+};
+
+static int stm32_iwdg_probe(struct platform_device *pdev)
+{
+	struct watchdog_device *wdd;
+	struct stm32_iwdg *wdt;
+	struct resource *res;
+	void __iomem *regs;
+	struct clk *clk;
+	int ret;
+
+	/* This is the timer base. */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(regs)) {
+		dev_err(&pdev->dev, "Could not get resource\n");
+		return PTR_ERR(regs);
+	}
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "Unable to get clock\n");
+		return PTR_ERR(clk);
+	}
+
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to prepare clock %p\n", clk);
+		return ret;
+	}
+
+	/*
+	 * Allocate our watchdog driver data, which has the
+	 * struct watchdog_device nested within it.
+	 */
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	/* Initialize struct stm32_iwdg. */
+	wdt->regs = regs;
+	wdt->clk = clk;
+	wdt->rate = clk_get_rate(clk);
+
+	/* Initialize struct watchdog_device. */
+	wdd = &wdt->wdd;
+	wdd->info = &stm32_iwdg_info;
+	wdd->ops = &stm32_iwdg_ops;
+	wdd->min_timeout = ((RLR_MIN + 1) * 256) / wdt->rate;
+	wdd->max_hw_heartbeat_ms = ((RLR_MAX + 1) * 256 * 1000) / wdt->rate;
+	wdd->parent = &pdev->dev;
+
+	watchdog_set_drvdata(wdd, wdt);
+	watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT);
+
+	ret = watchdog_init_timeout(wdd, 0, &pdev->dev);
+	if (ret)
+		dev_warn(&pdev->dev,
+			 "unable to set timeout value, using default\n");
+
+	ret = watchdog_register_device(wdd);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register watchdog device\n");
+		goto err;
+	}
+
+	platform_set_drvdata(pdev, wdt);
+
+	return 0;
+err:
+	clk_disable_unprepare(clk);
+
+	return ret;
+}
+
+static int stm32_iwdg_remove(struct platform_device *pdev)
+{
+	struct stm32_iwdg *wdt = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&wdt->wdd);
+	clk_disable_unprepare(wdt->clk);
+
+	return 0;
+}
+
+static const struct of_device_id stm32_iwdg_of_match[] = {
+	{ .compatible = "st,stm32-iwdg" },
+	{ /* end node */ }
+};
+MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
+
+static struct platform_driver stm32_iwdg_driver = {
+	.probe		= stm32_iwdg_probe,
+	.remove		= stm32_iwdg_remove,
+	.driver = {
+		.name	= "iwdg",
+		.of_match_table = stm32_iwdg_of_match,
+	},
+};
+module_platform_driver(stm32_iwdg_driver);
+
+MODULE_AUTHOR("Yannick Fertre <yannick.fertre@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 Independent Watchdog Driver");
+MODULE_LICENSE("GPL v2");

drivers/watchdog/uniphier_wdt.c

+/*
+ * Watchdog driver for the UniPhier watchdog timer
+ *
+ * (c) Copyright 2014 Panasonic Corporation
+ * (c) Copyright 2016 Socionext Inc.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.h>
+
+/* WDT timer setting register */
+#define WDTTIMSET			0x3004
+#define   WDTTIMSET_PERIOD_MASK		(0xf << 0)
+#define   WDTTIMSET_PERIOD_1_SEC	(0x3 << 0)
+
+/* WDT reset selection register */
+#define WDTRSTSEL			0x3008
+#define   WDTRSTSEL_RSTSEL_MASK		(0x3 << 0)
+#define   WDTRSTSEL_RSTSEL_BOTH		(0x0 << 0)
+#define   WDTRSTSEL_RSTSEL_IRQ_ONLY	(0x2 << 0)
+
+/* WDT control register */
+#define WDTCTRL				0x300c
+#define   WDTCTRL_STATUS		BIT(8)
+#define   WDTCTRL_CLEAR			BIT(1)
+#define   WDTCTRL_ENABLE		BIT(0)
+
+#define SEC_TO_WDTTIMSET_PRD(sec) \
+		(ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)
+
+#define WDTST_TIMEOUT			1000 /* usec */
+
+#define WDT_DEFAULT_TIMEOUT		64   /* Default is 64 seconds */
+#define WDT_PERIOD_MIN			1
+#define WDT_PERIOD_MAX			128
+
+static unsigned int timeout = 0;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+struct uniphier_wdt_dev {
+	struct watchdog_device wdt_dev;
+	struct regmap	*regmap;
+};
+
+/*
+ * UniPhier Watchdog operations
+ */
+static int uniphier_watchdog_ping(struct watchdog_device *w)
+{
+	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+	unsigned int val;
+	int ret;
+
+	/* Clear counter */
+	ret = regmap_write_bits(wdev->regmap, WDTCTRL,
+				WDTCTRL_CLEAR, WDTCTRL_CLEAR);
+	if (!ret)
+		/*
+		 * As SoC specification, after clear counter,
+		 * it needs to wait until counter status is 1.
+		 */
+		ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
+					       (val & WDTCTRL_STATUS),
+					       0, WDTST_TIMEOUT);
+
+	return ret;
+}
+
+static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
+{
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
+				       !(val & WDTCTRL_STATUS),
+				       0, WDTST_TIMEOUT);
+	if (ret)
+		return ret;
+
+	/* Setup period */
+	ret = regmap_write(regmap, WDTTIMSET,
+			   SEC_TO_WDTTIMSET_PRD(sec));
+	if (ret)
+		return ret;
+
+	/* Enable and clear watchdog */
+	ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
+	if (!ret)
+		/*
+		 * As SoC specification, after clear counter,
+		 * it needs to wait until counter status is 1.
+		 */
+		ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
+					       (val & WDTCTRL_STATUS),
+					       0, WDTST_TIMEOUT);
+
+	return ret;
+}
+
+static int __uniphier_watchdog_stop(struct regmap *regmap)
+{
+	/* Disable and stop watchdog */
+	return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
+}
+
+static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
+{
+	int ret;
+
+	ret = __uniphier_watchdog_stop(regmap);
+	if (ret)
+		return ret;
+
+	return __uniphier_watchdog_start(regmap, sec);
+}
+
+static int uniphier_watchdog_start(struct watchdog_device *w)
+{
+	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+	unsigned int tmp_timeout;
+
+	tmp_timeout = roundup_pow_of_two(w->timeout);
+
+	return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
+}
+
+static int uniphier_watchdog_stop(struct watchdog_device *w)
+{
+	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+
+	return __uniphier_watchdog_stop(wdev->regmap);
+}
+
+static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
+					 unsigned int t)
+{
+	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
+	unsigned int tmp_timeout;
+	int ret;
+
+	tmp_timeout = roundup_pow_of_two(t);
+	if (tmp_timeout == w->timeout)
+		return 0;
+
+	if (watchdog_active(w)) {
+		ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
+		if (ret)
+			return ret;
+	}
+
+	w->timeout = tmp_timeout;
+
+	return 0;
+}
+
+/*
+ * Kernel Interfaces
+ */
+static const struct watchdog_info uniphier_wdt_info = {
+	.identity	= "uniphier-wdt",
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE |
+			  WDIOF_OVERHEAT,
+};
+
+static const struct watchdog_ops uniphier_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= uniphier_watchdog_start,
+	.stop		= uniphier_watchdog_stop,
+	.ping		= uniphier_watchdog_ping,
+	.set_timeout	= uniphier_watchdog_set_timeout,
+};
+
+static int uniphier_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct uniphier_wdt_dev *wdev;
+	struct regmap *regmap;
+	struct device_node *parent;
+	int ret;
+
+	wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
+	if (!wdev)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, wdev);
+
+	parent = of_get_parent(dev->of_node); /* parent should be syscon node */
+	regmap = syscon_node_to_regmap(parent);
+	of_node_put(parent);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	wdev->regmap = regmap;
+	wdev->wdt_dev.info = &uniphier_wdt_info;
+	wdev->wdt_dev.ops = &uniphier_wdt_ops;
+	wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
+	wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
+	wdev->wdt_dev.parent = dev;
+
+	if (watchdog_init_timeout(&wdev->wdt_dev, timeout, dev) < 0) {
+		wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
+	}
+	watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
+	watchdog_stop_on_reboot(&wdev->wdt_dev);
+
+	watchdog_set_drvdata(&wdev->wdt_dev, wdev);
+
+	uniphier_watchdog_stop(&wdev->wdt_dev);
+	ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
+	if (ret)
+		return ret;
+
+	ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
+		 wdev->wdt_dev.timeout, nowayout);
+
+	return 0;
+}
+
+static const struct of_device_id uniphier_wdt_dt_ids[] = {
+	{ .compatible = "socionext,uniphier-wdt" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);
+
+static struct platform_driver uniphier_wdt_driver = {
+	.probe		= uniphier_wdt_probe,
+	.driver		= {
+		.name		= "uniphier-wdt",
+		.of_match_table	= uniphier_wdt_dt_ids,
+	},
+};
+
+module_platform_driver(uniphier_wdt_driver);
+
+module_param(timeout, uint, 0000);
+MODULE_PARM_DESC(timeout,
+	"Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
+				__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
+
+module_param(nowayout, bool, 0000);
+MODULE_PARM_DESC(nowayout,
+	"Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
+MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
+MODULE_LICENSE("GPL v2");

drivers/watchdog/w83627hf_wdt.c

@@ -49,7 +49,8 @@ static int cr_wdt_csr;		/* WDT control & status register */
 
 enum chips { w83627hf, w83627s, w83697hf, w83697ug, w83637hf, w83627thf,
 	     w83687thf, w83627ehf, w83627dhg, w83627uhg, w83667hg, w83627dhg_p,
-	     w83667hg_b, nct6775, nct6776, nct6779, nct6791, nct6792, nct6102 };
+	     w83667hg_b, nct6775, nct6776, nct6779, nct6791, nct6792, nct6793,
+	     nct6795, nct6102 };
 
 static int timeout;			/* in seconds */
 module_param(timeout, int, 0);
@@ -97,6 +98,8 @@ MODULE_PARM_DESC(early_disable, "Disable watchdog at boot time (default=0)");
 #define NCT6779_ID		0xc5
 #define NCT6791_ID		0xc8
 #define NCT6792_ID		0xc9
+#define NCT6793_ID		0xd1
+#define NCT6795_ID		0xd3
 
 #define W83627HF_WDT_TIMEOUT	0xf6
 #define W83697HF_WDT_TIMEOUT	0xf4
@@ -204,6 +207,8 @@ static int w83627hf_init(struct watchdog_device *wdog, enum chips chip)
 	case nct6779:
 	case nct6791:
 	case nct6792:
+	case nct6793:
+	case nct6795:
 	case nct6102:
 		/*
 		 * These chips have a fixed WDTO# output pin (W83627UHG),
@@ -396,6 +401,12 @@ static int wdt_find(int addr)
 	case NCT6792_ID:
 		ret = nct6792;
 		break;
+	case NCT6793_ID:
+		ret = nct6793;
+		break;
+	case NCT6795_ID:
+		ret = nct6795;
+		break;
 	case NCT6102_ID:
 		ret = nct6102;
 		cr_wdt_timeout = NCT6102D_WDT_TIMEOUT;
@@ -437,6 +448,8 @@ static int __init wdt_init(void)
 		"NCT6779",
 		"NCT6791",
 		"NCT6792",
+		"NCT6793",
+		"NCT6795",
 		"NCT6102",
 	};
 

drivers/watchdog/watchdog_dev.c

@@ -80,6 +80,9 @@ static struct watchdog_core_data *old_wd_data;
 
 static struct workqueue_struct *watchdog_wq;
 
+static bool handle_boot_enabled =
+	IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED);
+
 static inline bool watchdog_need_worker(struct watchdog_device *wdd)
 {
 	/* All variables in milli-seconds */
@@ -192,18 +195,23 @@ static int watchdog_ping(struct watchdog_device *wdd)
 	return __watchdog_ping(wdd);
 }
 
+static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data)
+{
+	struct watchdog_device *wdd = wd_data->wdd;
+
+	return wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd));
+}
+
 static void watchdog_ping_work(struct work_struct *work)
 {
 	struct watchdog_core_data *wd_data;
-	struct watchdog_device *wdd;
 
 	wd_data = container_of(to_delayed_work(work), struct watchdog_core_data,
 			       work);
 
 	mutex_lock(&wd_data->lock);
-	wdd = wd_data->wdd;
-	if (wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd)))
-		__watchdog_ping(wdd);
+	if (watchdog_worker_should_ping(wd_data))
+		__watchdog_ping(wd_data->wdd);
 	mutex_unlock(&wd_data->lock);
 }
 
@@ -956,9 +964,14 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno)
 	 * and schedule an immediate ping.
 	 */
 	if (watchdog_hw_running(wdd)) {
-		__module_get(wdd->ops->owner);
-		kref_get(&wd_data->kref);
-		queue_delayed_work(watchdog_wq, &wd_data->work, 0);
+		if (handle_boot_enabled) {
+			__module_get(wdd->ops->owner);
+			kref_get(&wd_data->kref);
+			queue_delayed_work(watchdog_wq, &wd_data->work, 0);
+		} else {
+			pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n",
+					wdd->id);
+		}
 	}
 
 	return 0;
@@ -1106,3 +1119,8 @@ void __exit watchdog_dev_exit(void)
 	class_unregister(&watchdog_class);
 	destroy_workqueue(watchdog_wq);
 }
+
+module_param(handle_boot_enabled, bool, 0444);
+MODULE_PARM_DESC(handle_boot_enabled,
+	"Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default="
+	__MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")");

drivers/watchdog/zx2967_wdt.c

@@ -154,7 +154,7 @@ static const struct watchdog_info zx2967_wdt_ident = {
 	.identity         =	"zx2967 watchdog",
 };
 
-static struct watchdog_ops zx2967_wdt_ops = {
+static const struct watchdog_ops zx2967_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = zx2967_wdt_start,
 	.stop = zx2967_wdt_stop,