diff mbox series

[v6,2/2] watchdog: Add Renesas RZ/N1 Watchdog driver

Message ID 20220413082527.155740-3-jjhiblot@traphandler.com
State Superseded
Headers show
Series ARM: r9a06g032: add support for the watchdogs | expand

Commit Message

Jean-Jacques Hiblot April 13, 2022, 8:25 a.m. UTC
From: Phil Edworthy <phil.edworthy@renesas.com>

This is a driver for the standard WDT on the RZ/N1 devices. This WDT has
very limited timeout capabilities. However, it can reset the device.
To do so, the corresponding bits in the SysCtrl RSTEN register need to
be enabled. This is not done by this driver.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
---
 drivers/watchdog/Kconfig    |   8 ++
 drivers/watchdog/Makefile   |   1 +
 drivers/watchdog/rzn1_wdt.c | 203 ++++++++++++++++++++++++++++++++++++
 3 files changed, 212 insertions(+)
 create mode 100644 drivers/watchdog/rzn1_wdt.c

Comments

Geert Uytterhoeven April 27, 2022, 12:32 p.m. UTC | #1
Hi Jean-Jacques,

On Wed, Apr 13, 2022 at 10:25 AM Jean-Jacques Hiblot
<jjhiblot@traphandler.com> wrote:
> From: Phil Edworthy <phil.edworthy@renesas.com>
>
> This is a driver for the standard WDT on the RZ/N1 devices. This WDT has
> very limited timeout capabilities. However, it can reset the device.
> To do so, the corresponding bits in the SysCtrl RSTEN register need to
> be enabled. This is not done by this driver.
>
> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>

Thanks for your patch!

> --- /dev/null
> +++ b/drivers/watchdog/rzn1_wdt.c

> +static int rzn1_wdt_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct rzn1_watchdog *wdt;
> +       struct device_node *np = dev->of_node;
> +       struct clk *clk;
> +       int ret;
> +       int irq;
> +
> +       wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> +       if (!wdt)
> +               return -ENOMEM;
> +
> +       wdt->base = devm_platform_ioremap_resource(pdev, 0);
> +       if (IS_ERR(wdt->base))
> +               return PTR_ERR(wdt->base);
> +
> +       irq = platform_get_irq(pdev, 0);
> +       if (irq < 0)
> +               return irq;
> +
> +       ret = devm_request_irq(dev, irq, rzn1_wdt_irq, 0,
> +                              np->name, wdt);
> +       if (ret) {
> +               dev_err(dev, "failed to request irq %d\n", irq);
> +               return ret;
> +       }
> +
> +       clk = devm_clk_get(dev, NULL);
> +       if (IS_ERR(clk)) {
> +               dev_err(dev, "failed to get the clock\n");
> +               return PTR_ERR(clk);
> +       }
> +
> +       ret = clk_prepare_enable(clk);
> +       if (ret) {
> +               dev_err(dev, "failed to prepare/enable the clock\n");
> +               return ret;
> +       }
> +
> +       ret = devm_add_action_or_reset(dev, rzn1_wdt_clk_disable_unprepare,
> +                                      clk);
> +       if (ret) {
> +               dev_err(dev, "failed to register clock unprepare callback\n");

Please remove this error message.
devm_add_action_or_reset() only fails when running out of memory,
in which case the memory allocation core has already printed an
error message.

> +               return ret;
> +       }

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Guenter Roeck April 27, 2022, 1:03 p.m. UTC | #2
On 4/13/22 01:25, Jean-Jacques Hiblot wrote:
> From: Phil Edworthy <phil.edworthy@renesas.com>
> 
> This is a driver for the standard WDT on the RZ/N1 devices. This WDT has
> very limited timeout capabilities. However, it can reset the device.
> To do so, the corresponding bits in the SysCtrl RSTEN register need to
> be enabled. This is not done by this driver.
> 
> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
> ---
>   drivers/watchdog/Kconfig    |   8 ++
>   drivers/watchdog/Makefile   |   1 +
>   drivers/watchdog/rzn1_wdt.c | 203 ++++++++++++++++++++++++++++++++++++
>   3 files changed, 212 insertions(+)
>   create mode 100644 drivers/watchdog/rzn1_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index c4e82a8d863f..4d5e503c8950 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -883,6 +883,14 @@ config RENESAS_RZAWDT
>   	  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 RENESAS_RZN1WDT
> +	tristate "Renesas RZ/N1 watchdog"
> +	depends on ARCH_RENESAS || COMPILE_TEST
> +	select WATCHDOG_CORE
> +	help
> +	  This driver adds watchdog support for the integrated watchdogs in the
> +	  Renesas RZ/N1 SoCs. These watchdogs can be used to reset a system.
> +
>   config RENESAS_RZG2LWDT
>   	tristate "Renesas RZ/G2L WDT Watchdog"
>   	depends on ARCH_RENESAS || COMPILE_TEST
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index f7da867e8782..38d38564f47b 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -84,6 +84,7 @@ obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
>   obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
>   obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
>   obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
> +obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o
>   obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o
>   obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
>   obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
> diff --git a/drivers/watchdog/rzn1_wdt.c b/drivers/watchdog/rzn1_wdt.c
> new file mode 100644
> index 000000000000..fa32716727b7
> --- /dev/null
> +++ b/drivers/watchdog/rzn1_wdt.c
> @@ -0,0 +1,203 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/N1 Watchdog timer.
> + * This is a 12-bit timer driver from a (62.5/16384) MHz clock. It can't even
> + * cope with 2 seconds.
> + *
> + * Copyright 2018 Renesas Electronics Europe Ltd.
> + *
> + * Derived from Ralink RT288x watchdog timer.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/watchdog.h>
> +
> +#define DEFAULT_TIMEOUT		60
> +
> +#define RZN1_WDT_RETRIGGER			0x0
> +#define RZN1_WDT_RETRIGGER_RELOAD_VAL		0
> +#define RZN1_WDT_RETRIGGER_RELOAD_VAL_MASK	0xfff
> +#define RZN1_WDT_RETRIGGER_PRESCALE		BIT(12)
> +#define RZN1_WDT_RETRIGGER_ENABLE		BIT(13)
> +#define RZN1_WDT_RETRIGGER_WDSI			(0x2 << 14)
> +
> +#define RZN1_WDT_PRESCALER			16384
> +#define RZN1_WDT_MAX				4095
> +
> +struct rzn1_watchdog {
> +	struct watchdog_device		wdtdev;
> +	void __iomem			*base;
> +	unsigned long			clk_rate;

Nit: Whenever clk_rate is used, it is divided by 1000.
It might be better to store and use clk_rate_khz instead.

Guenter
Jean-Jacques Hiblot April 27, 2022, 1:33 p.m. UTC | #3
On 27/04/2022 14:32, Geert Uytterhoeven wrote:
> Hi Jean-Jacques,
>
> On Wed, Apr 13, 2022 at 10:25 AM Jean-Jacques Hiblot
> <jjhiblot@traphandler.com> wrote:
>> From: Phil Edworthy <phil.edworthy@renesas.com>
>>
>> This is a driver for the standard WDT on the RZ/N1 devices. This WDT has
>> very limited timeout capabilities. However, it can reset the device.
>> To do so, the corresponding bits in the SysCtrl RSTEN register need to
>> be enabled. This is not done by this driver.
>>
>> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
>> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
> Thanks for your patch!
>
>> --- /dev/null
>> +++ b/drivers/watchdog/rzn1_wdt.c
>> +static int rzn1_wdt_probe(struct platform_device *pdev)
>> +{
>> +       struct device *dev = &pdev->dev;
>> +       struct rzn1_watchdog *wdt;
>> +       struct device_node *np = dev->of_node;
>> +       struct clk *clk;
>> +       int ret;
>> +       int irq;
>> +
>> +       wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>> +       if (!wdt)
>> +               return -ENOMEM;
>> +
>> +       wdt->base = devm_platform_ioremap_resource(pdev, 0);
>> +       if (IS_ERR(wdt->base))
>> +               return PTR_ERR(wdt->base);
>> +
>> +       irq = platform_get_irq(pdev, 0);
>> +       if (irq < 0)
>> +               return irq;
>> +
>> +       ret = devm_request_irq(dev, irq, rzn1_wdt_irq, 0,
>> +                              np->name, wdt);
>> +       if (ret) {
>> +               dev_err(dev, "failed to request irq %d\n", irq);
>> +               return ret;
>> +       }
>> +
>> +       clk = devm_clk_get(dev, NULL);
>> +       if (IS_ERR(clk)) {
>> +               dev_err(dev, "failed to get the clock\n");
>> +               return PTR_ERR(clk);
>> +       }
>> +
>> +       ret = clk_prepare_enable(clk);
>> +       if (ret) {
>> +               dev_err(dev, "failed to prepare/enable the clock\n");
>> +               return ret;
>> +       }
>> +
>> +       ret = devm_add_action_or_reset(dev, rzn1_wdt_clk_disable_unprepare,
>> +                                      clk);
>> +       if (ret) {
>> +               dev_err(dev, "failed to register clock unprepare callback\n");
> Please remove this error message.
> devm_add_action_or_reset() only fails when running out of memory,
> in which case the memory allocation core has already printed an
> error message.

OK. I'll remove this.

Thanks,

JJ

>
>> +               return ret;
>> +       }
> Gr{oetje,eeting}s,
>
>                          Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                  -- Linus Torvalds
Jean-Jacques Hiblot April 27, 2022, 1:36 p.m. UTC | #4
On 27/04/2022 15:03, Guenter Roeck wrote:
> On 4/13/22 01:25, Jean-Jacques Hiblot wrote:
>> From: Phil Edworthy <phil.edworthy@renesas.com>
>>
>> This is a driver for the standard WDT on the RZ/N1 devices. This WDT has
>> very limited timeout capabilities. However, it can reset the device.
>> To do so, the corresponding bits in the SysCtrl RSTEN register need to
>> be enabled. This is not done by this driver.
>>
>> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
>> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
>> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
>> ---
>>   drivers/watchdog/Kconfig    |   8 ++
>>   drivers/watchdog/Makefile   |   1 +
>>   drivers/watchdog/rzn1_wdt.c | 203 ++++++++++++++++++++++++++++++++++++
>>   3 files changed, 212 insertions(+)
>>   create mode 100644 drivers/watchdog/rzn1_wdt.c
>>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index c4e82a8d863f..4d5e503c8950 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -883,6 +883,14 @@ config RENESAS_RZAWDT
>>         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 RENESAS_RZN1WDT
>> +    tristate "Renesas RZ/N1 watchdog"
>> +    depends on ARCH_RENESAS || COMPILE_TEST
>> +    select WATCHDOG_CORE
>> +    help
>> +      This driver adds watchdog support for the integrated watchdogs 
>> in the
>> +      Renesas RZ/N1 SoCs. These watchdogs can be used to reset a 
>> system.
>> +
>>   config RENESAS_RZG2LWDT
>>       tristate "Renesas RZ/G2L WDT Watchdog"
>>       depends on ARCH_RENESAS || COMPILE_TEST
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index f7da867e8782..38d38564f47b 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -84,6 +84,7 @@ obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
>>   obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
>>   obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
>>   obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
>> +obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o
>>   obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o
>>   obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
>>   obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
>> diff --git a/drivers/watchdog/rzn1_wdt.c b/drivers/watchdog/rzn1_wdt.c
>> new file mode 100644
>> index 000000000000..fa32716727b7
>> --- /dev/null
>> +++ b/drivers/watchdog/rzn1_wdt.c
>> @@ -0,0 +1,203 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Renesas RZ/N1 Watchdog timer.
>> + * This is a 12-bit timer driver from a (62.5/16384) MHz clock. It 
>> can't even
>> + * cope with 2 seconds.
>> + *
>> + * Copyright 2018 Renesas Electronics Europe Ltd.
>> + *
>> + * Derived from Ralink RT288x watchdog timer.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_irq.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/reboot.h>
>> +#include <linux/watchdog.h>
>> +
>> +#define DEFAULT_TIMEOUT        60
>> +
>> +#define RZN1_WDT_RETRIGGER            0x0
>> +#define RZN1_WDT_RETRIGGER_RELOAD_VAL        0
>> +#define RZN1_WDT_RETRIGGER_RELOAD_VAL_MASK    0xfff
>> +#define RZN1_WDT_RETRIGGER_PRESCALE        BIT(12)
>> +#define RZN1_WDT_RETRIGGER_ENABLE        BIT(13)
>> +#define RZN1_WDT_RETRIGGER_WDSI            (0x2 << 14)
>> +
>> +#define RZN1_WDT_PRESCALER            16384
>> +#define RZN1_WDT_MAX                4095
>> +
>> +struct rzn1_watchdog {
>> +    struct watchdog_device        wdtdev;
>> +    void __iomem            *base;
>> +    unsigned long            clk_rate;
>
> Nit: Whenever clk_rate is used, it is divided by 1000.
> It might be better to store and use clk_rate_khz instead.

OK. I'll change this.

Thanks,

JJ

>
> Guenter
diff mbox series

Patch

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index c4e82a8d863f..4d5e503c8950 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -883,6 +883,14 @@  config RENESAS_RZAWDT
 	  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 RENESAS_RZN1WDT
+	tristate "Renesas RZ/N1 watchdog"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	select WATCHDOG_CORE
+	help
+	  This driver adds watchdog support for the integrated watchdogs in the
+	  Renesas RZ/N1 SoCs. These watchdogs can be used to reset a system.
+
 config RENESAS_RZG2LWDT
 	tristate "Renesas RZ/G2L WDT Watchdog"
 	depends on ARCH_RENESAS || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index f7da867e8782..38d38564f47b 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -84,6 +84,7 @@  obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
 obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
 obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
 obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
+obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o
 obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o
 obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
 obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
diff --git a/drivers/watchdog/rzn1_wdt.c b/drivers/watchdog/rzn1_wdt.c
new file mode 100644
index 000000000000..fa32716727b7
--- /dev/null
+++ b/drivers/watchdog/rzn1_wdt.c
@@ -0,0 +1,203 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/N1 Watchdog timer.
+ * This is a 12-bit timer driver from a (62.5/16384) MHz clock. It can't even
+ * cope with 2 seconds.
+ *
+ * Copyright 2018 Renesas Electronics Europe Ltd.
+ *
+ * Derived from Ralink RT288x watchdog timer.
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+
+#define DEFAULT_TIMEOUT		60
+
+#define RZN1_WDT_RETRIGGER			0x0
+#define RZN1_WDT_RETRIGGER_RELOAD_VAL		0
+#define RZN1_WDT_RETRIGGER_RELOAD_VAL_MASK	0xfff
+#define RZN1_WDT_RETRIGGER_PRESCALE		BIT(12)
+#define RZN1_WDT_RETRIGGER_ENABLE		BIT(13)
+#define RZN1_WDT_RETRIGGER_WDSI			(0x2 << 14)
+
+#define RZN1_WDT_PRESCALER			16384
+#define RZN1_WDT_MAX				4095
+
+struct rzn1_watchdog {
+	struct watchdog_device		wdtdev;
+	void __iomem			*base;
+	unsigned long			clk_rate;
+};
+
+static inline uint32_t get_max_heart_beat(unsigned long clk_rate)
+{
+	return (RZN1_WDT_MAX * RZN1_WDT_PRESCALER) / (clk_rate / 1000);
+}
+
+static inline uint32_t compute_reload_value(uint32_t tick_ms,
+					    unsigned long clk_rate)
+{
+	return (tick_ms * (clk_rate / 1000)) / RZN1_WDT_PRESCALER;
+}
+
+static int rzn1_wdt_ping(struct watchdog_device *w)
+{
+	struct rzn1_watchdog *wdt = watchdog_get_drvdata(w);
+
+	/* Any value retrigggers the watchdog */
+	writel(0, wdt->base + RZN1_WDT_RETRIGGER);
+
+	return 0;
+}
+
+static int rzn1_wdt_start(struct watchdog_device *w)
+{
+	struct rzn1_watchdog *wdt = watchdog_get_drvdata(w);
+	u32 val;
+
+	/*
+	 * The hardware allows you to write to this reg only once.
+	 * Since this includes the reload value, there is no way to change the
+	 * timeout once started. Also note that the WDT clock is half the bus
+	 * fabric clock rate, so if the bus fabric clock rate is changed after
+	 * the WDT is started, the WDT interval will be wrong.
+	 */
+	val = RZN1_WDT_RETRIGGER_WDSI;
+	val |= RZN1_WDT_RETRIGGER_ENABLE;
+	val |= RZN1_WDT_RETRIGGER_PRESCALE;
+	val |= compute_reload_value(w->max_hw_heartbeat_ms, wdt->clk_rate);
+	writel(val, wdt->base + RZN1_WDT_RETRIGGER);
+
+	return 0;
+}
+
+static irqreturn_t rzn1_wdt_irq(int irq, void *_wdt)
+{
+	pr_crit("RZN1 Watchdog. Initiating system reboot\n");
+	emergency_restart();
+
+	return IRQ_HANDLED;
+}
+
+static struct watchdog_info rzn1_wdt_info = {
+	.identity = "RZ/N1 Watchdog",
+	.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+};
+
+static const struct watchdog_ops rzn1_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = rzn1_wdt_start,
+	.ping = rzn1_wdt_ping,
+};
+
+static void rzn1_wdt_clk_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static int rzn1_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rzn1_watchdog *wdt;
+	struct device_node *np = dev->of_node;
+	struct clk *clk;
+	int ret;
+	int irq;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(wdt->base))
+		return PTR_ERR(wdt->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_irq(dev, irq, rzn1_wdt_irq, 0,
+			       np->name, wdt);
+	if (ret) {
+		dev_err(dev, "failed to request irq %d\n", irq);
+		return ret;
+	}
+
+	clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(dev, "failed to get the clock\n");
+		return PTR_ERR(clk);
+	}
+
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		dev_err(dev, "failed to prepare/enable the clock\n");
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(dev, rzn1_wdt_clk_disable_unprepare,
+				       clk);
+	if (ret) {
+		dev_err(dev, "failed to register clock unprepare callback\n");
+		return ret;
+	}
+
+	wdt->clk_rate = clk_get_rate(clk);
+	if (!wdt->clk_rate) {
+		dev_err(dev, "failed to get the clock rate\n");
+		return -EINVAL;
+	}
+
+	wdt->wdtdev.info = &rzn1_wdt_info,
+	wdt->wdtdev.ops = &rzn1_wdt_ops,
+	wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS,
+	wdt->wdtdev.parent = dev;
+	/*
+	 * The period of the watchdog cannot be changed once set
+	 * and is limited to a very short period.
+	 * Configure it for a 1s period once and for all, and
+	 * rely on the heart-beat provided by the watchdog core
+	 * to make this usable by the user-space.
+	 */
+	wdt->wdtdev.max_hw_heartbeat_ms = get_max_heart_beat(wdt->clk_rate);
+	if (wdt->wdtdev.max_hw_heartbeat_ms > 1000)
+		wdt->wdtdev.max_hw_heartbeat_ms = 1000;
+
+	wdt->wdtdev.timeout = DEFAULT_TIMEOUT;
+	ret = watchdog_init_timeout(&wdt->wdtdev, 0, dev);
+	if (ret)
+		return ret;
+
+	watchdog_set_drvdata(&wdt->wdtdev, wdt);
+
+	return devm_watchdog_register_device(dev, &wdt->wdtdev);
+}
+
+
+static const struct of_device_id rzn1_wdt_match[] = {
+	{ .compatible = "renesas,rzn1-wdt" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, rzn1_wdt_match);
+
+static struct platform_driver rzn1_wdt_driver = {
+	.probe		= rzn1_wdt_probe,
+	.driver		= {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= rzn1_wdt_match,
+	},
+};
+
+module_platform_driver(rzn1_wdt_driver);
+
+MODULE_DESCRIPTION("Renesas RZ/N1 hardware watchdog");
+MODULE_AUTHOR("Phil Edworthy <phil.edworthy@renesas.com>");
+MODULE_LICENSE("GPL");