[PATCH v3 1/3] watchdog: Add pm8916 watchdog driver

[PATCH v3 1/3] watchdog: Add pm8916 watchdog driver

[Loic Poulain]

The PM816 module is a versatile PMIC with many diverse functions
integrated, including, a watchdog.
This watchdog is subcomponent of the PON (Power On) peripheral,
in the same way as pwrkey/resin buttons.
It works with two timers (2-stages), the first one generates an
IRQ to the main SoC (APQ8016/MSM8916), the second one performs
the reset.

This driver expects the following device hierarchy:
[pm8916]->[pm8916-pon]->[pm8916-wdt]

It uses the pm8916 regmap to access PM8916 registers.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
---
 v2: SPDX license
     headers ordering
     coding styles / tabs / multi-line comments
     pretimeout / bark interrupt
     WDIOF_MAGICCLOSE flag
     timeout init via fdt
     devm usage
 v3: Remove unused dev/irq variables from pm8916 wdt struct

 drivers/watchdog/Kconfig      |   8 ++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/pm8916_wdt.c | 211 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 220 insertions(+)
 create mode 100644 drivers/watchdog/pm8916_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 2d64333..ef2c2b5 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -847,6 +847,14 @@ config SPRD_WATCHDOG
 	  Say Y here to include watchdog timer supported
 	  by Spreadtrum system.
 
+config PM8916_WATCHDOG
+	tristate "QCOM PM8916 pmic watchdog"
+	depends on OF && MFD_SPMI_PMIC
+	select WATCHDOG_CORE
+	help
+	  Say Y here to include support watchdog timer embedded into the
+	  pm8916 module.
+
 # X86 (i386 + ia64 + x86_64) Architecture
 
 config ACQUIRE_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index f69cdff..cc90e72 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -92,6 +92,7 @@ obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
 obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
 obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o
 obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o
+obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
 
 # X86 (i386 + ia64 + x86_64) Architecture
 obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
diff --git a/drivers/watchdog/pm8916_wdt.c b/drivers/watchdog/pm8916_wdt.c
new file mode 100644
index 0000000..7f10041
--- /dev/null
+++ b/drivers/watchdog/pm8916_wdt.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.h>
+
+#define PON_INT_RT_STS			0x10
+#define PMIC_WD_BARK_STS_BIT		BIT(6)
+
+#define PON_PMIC_WD_RESET_S1_TIMER	0x54
+#define PON_PMIC_WD_RESET_S2_TIMER	0x55
+
+#define PON_PMIC_WD_RESET_S2_CTL	0x56
+#define RESET_TYPE_WARM			0x01
+#define RESET_TYPE_SHUTDOWN		0x04
+#define RESET_TYPE_HARD			0x07
+
+#define PON_PMIC_WD_RESET_S2_CTL2	0x57
+#define S2_RESET_EN_BIT			BIT(7)
+
+#define PON_PMIC_WD_RESET_PET		0x58
+#define WATCHDOG_PET_BIT		BIT(0)
+
+#define PM8916_WDT_DEFAULT_TIMEOUT	32
+#define PM8916_WDT_MIN_TIMEOUT		1
+#define PM8916_WDT_MAX_TIMEOUT		127
+
+struct pm8916_wdt {
+	struct regmap *regmap;
+	struct watchdog_device wdev;
+	u32 baseaddr;
+};
+
+static int pm8916_wdt_start(struct watchdog_device *wdev)
+{
+	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+
+	return regmap_update_bits(wdt->regmap,
+				  wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
+				  S2_RESET_EN_BIT, S2_RESET_EN_BIT);
+}
+
+static int pm8916_wdt_stop(struct watchdog_device *wdev)
+{
+	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+
+	return regmap_update_bits(wdt->regmap,
+				  wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
+				  S2_RESET_EN_BIT, 0);
+}
+
+static int pm8916_wdt_ping(struct watchdog_device *wdev)
+{
+	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+
+	return regmap_update_bits(wdt->regmap,
+				  wdt->baseaddr + PON_PMIC_WD_RESET_PET,
+				  WATCHDOG_PET_BIT, WATCHDOG_PET_BIT);
+}
+
+static int pm8916_wdt_configure_timers(struct watchdog_device *wdev)
+{
+	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+	int err;
+
+	err = regmap_write(wdt->regmap,
+			   wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,
+			   wdev->timeout - wdev->pretimeout);
+	if (err)
+		return err;
+
+	return regmap_write(wdt->regmap,
+			    wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,
+			    wdev->pretimeout);
+}
+
+static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,
+				  unsigned int timeout)
+{
+	wdev->timeout = timeout;
+
+	return pm8916_wdt_configure_timers(wdev);
+}
+
+static int pm8916_wdt_set_pretimeout(struct watchdog_device *wdev,
+				     unsigned int pretimeout)
+{
+	wdev->pretimeout = pretimeout;
+
+	return pm8916_wdt_configure_timers(wdev);
+}
+
+static irqreturn_t pm8916_wdt_isr(int irq, void *arg)
+{
+	struct pm8916_wdt *wdt = arg;
+	int err, sts;
+
+	err = regmap_read(wdt->regmap, wdt->baseaddr + PON_INT_RT_STS, &sts);
+	if (err)
+		return IRQ_HANDLED;
+
+	if (sts & PMIC_WD_BARK_STS_BIT)
+		watchdog_notify_pretimeout(&wdt->wdev);
+
+	return IRQ_HANDLED;
+}
+
+static const struct watchdog_info pm8916_wdt_ident = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "QCOM PM8916 PON WDT",
+};
+
+static const struct watchdog_info pm8916_wdt_pt_ident = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
+		   WDIOF_PRETIMEOUT,
+	.identity = "QCOM PM8916 PON WDT",
+};
+
+static const struct watchdog_ops pm8916_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = pm8916_wdt_start,
+	.stop = pm8916_wdt_stop,
+	.ping = pm8916_wdt_ping,
+	.set_timeout = pm8916_wdt_set_timeout,
+	.set_pretimeout = pm8916_wdt_set_pretimeout,
+};
+
+static int pm8916_wdt_probe(struct platform_device *pdev)
+{
+	struct pm8916_wdt *wdt;
+	struct device *parent;
+	int err, irq;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	parent = pdev->dev.parent;
+
+	/*
+	 * The pm8916-pon-wdt is a child of the pon device, which is a child
+	 * of the pm8916 mfd device. We want access to the pm8916 registers.
+	 * Retrieve regmap from pm8916 (parent->parent) and base address
+	 * from pm8916-pon (pon).
+	 */
+	wdt->regmap = dev_get_regmap(parent->parent, NULL);
+	if (!wdt->regmap) {
+		dev_err(&pdev->dev, "failed to locate regmap\n");
+		return -ENODEV;
+	}
+
+	err = device_property_read_u32(parent, "reg", &wdt->baseaddr);
+	if (err) {
+		dev_err(&pdev->dev, "failed to get pm8916-pon address\n");
+		return err;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq > 0) {
+		if (devm_request_irq(&pdev->dev, irq, pm8916_wdt_isr, 0,
+				     "pm8916_wdt", wdt))
+			irq = 0;
+	}
+
+	/* Configure watchdog to hard-reset mode */
+	err = regmap_write(wdt->regmap,
+			   wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL,
+			   RESET_TYPE_HARD);
+	if (err) {
+		dev_err(&pdev->dev, "failed configure watchdog\n");
+		return err;
+	}
+
+	wdt->wdev.info = (irq > 0) ? &pm8916_wdt_pt_ident : &pm8916_wdt_ident,
+	wdt->wdev.ops = &pm8916_wdt_ops,
+	wdt->wdev.parent = &pdev->dev;
+	wdt->wdev.min_timeout = PM8916_WDT_MIN_TIMEOUT;
+	wdt->wdev.max_timeout = PM8916_WDT_MAX_TIMEOUT;
+	wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;
+	wdt->wdev.pretimeout = 0;
+	watchdog_set_drvdata(&wdt->wdev, wdt);
+
+	watchdog_init_timeout(&wdt->wdev, 0, &pdev->dev);
+	pm8916_wdt_configure_timers(&wdt->wdev);
+
+	return devm_watchdog_register_device(&pdev->dev, &wdt->wdev);
+}
+
+static const struct of_device_id pm8916_wdt_id_table[] = {
+	{ .compatible = "qcom,pm8916-wdt" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pm8916_wdt_id_table);
+
+static struct platform_driver pm8916_wdt_driver = {
+	.probe = pm8916_wdt_probe,
+	.driver = {
+		.name = "pm8916-wdt",
+		.of_match_table = of_match_ptr(pm8916_wdt_id_table),
+	},
+};
+module_platform_driver(pm8916_wdt_driver);
+
+MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

[PATCH v3 2/3] dt-bindings: watchdog: Add Qualcomm PM8916 watchdog

[Loic Poulain]

Document support for the Watchdog Timer (WDT) Controller in the
Qualcomm PM8916 PMIC module.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
---
 v2: Add interrupts and timeout-sec props
 v3: Reword props summary

 .../bindings/watchdog/qcom,pm8916-wdt.txt          | 28 ++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt

diff --git a/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt b/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt
new file mode 100644
index 0000000..6fb984f
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt
@@ -0,0 +1,28 @@
+QCOM PM8916 watchdog timer controller
+
+This pm8916 watchdog timer controller must be under pm8916-pon node.
+
+Required properties:
+- compatible: should be "qcom,pm8916-wdt"
+
+Optional properties :
+- interrupts : Watchdog pre-timeout (bark) interrupt.
+- timeout-sec : Watchdog timeout value in seconds.
+
+Example:
+
+	pm8916_0: pm8916@0 {
+		compatible = "qcom,pm8916", "qcom,spmi-pmic";
+		reg = <0x0 SPMI_USID>;
+
+		pon@800 {
+			compatible = "qcom,pm8916-pon";
+			reg = <0x800>;
+
+			watchdog {
+				compatible = "qcom,pm8916-wdt";
+				interrupts = <0x0 0x8 6 IRQ_TYPE_EDGE_RISING>;
+				timeout-sec = <10>;
+			};
+		};
+	};
-- 
2.7.4

Re: [PATCH v3 2/3] dt-bindings: watchdog: Add Qualcomm PM8916 watchdog

[Rob Herring]

On Fri, 23 Nov 2018 09:44:37 +0100, Loic Poulain wrote:
> Document support for the Watchdog Timer (WDT) Controller in the
> Qualcomm PM8916 PMIC module.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>  v2: Add interrupts and timeout-sec props
>  v3: Reword props summary
> 
>  .../bindings/watchdog/qcom,pm8916-wdt.txt          | 28 ++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH v3 2/3] dt-bindings: watchdog: Add Qualcomm PM8916 watchdog

[Rob Herring]

On Fri, 23 Nov 2018 09:44:37 +0100, Loic Poulain wrote:
> Document support for the Watchdog Timer (WDT) Controller in the
> Qualcomm PM8916 PMIC module.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> ---
>  v2: Add interrupts and timeout-sec props
>  v3: Reword props summary
> 
>  .../bindings/watchdog/qcom,pm8916-wdt.txt          | 28 ++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [v3,2/3] dt-bindings: watchdog: Add Qualcomm PM8916 watchdog

[Guenter Roeck]

On Fri, Nov 23, 2018 at 09:44:37AM +0100, Loic Poulain wrote:
> Document support for the Watchdog Timer (WDT) Controller in the
> Qualcomm PM8916 PMIC module.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> Reviewed-by: Rob Herring <robh@kernel.org>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  v2: Add interrupts and timeout-sec props
>  v3: Reword props summary
> 
>  .../bindings/watchdog/qcom,pm8916-wdt.txt          | 28 ++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt b/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt
> new file mode 100644
> index 0000000..6fb984f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt
> @@ -0,0 +1,28 @@
> +QCOM PM8916 watchdog timer controller
> +
> +This pm8916 watchdog timer controller must be under pm8916-pon node.
> +
> +Required properties:
> +- compatible: should be "qcom,pm8916-wdt"
> +
> +Optional properties :
> +- interrupts : Watchdog pre-timeout (bark) interrupt.
> +- timeout-sec : Watchdog timeout value in seconds.
> +
> +Example:
> +
> +	pm8916_0: pm8916@0 {
> +		compatible = "qcom,pm8916", "qcom,spmi-pmic";
> +		reg = <0x0 SPMI_USID>;
> +
> +		pon@800 {
> +			compatible = "qcom,pm8916-pon";
> +			reg = <0x800>;
> +
> +			watchdog {
> +				compatible = "qcom,pm8916-wdt";
> +				interrupts = <0x0 0x8 6 IRQ_TYPE_EDGE_RISING>;
> +				timeout-sec = <10>;
> +			};
> +		};
> +	};

[PATCH v3 3/3] arm64: dts: qcom: pm8916: Add PON watchdog node

[Loic Poulain]

Add watchdog child node to the PM8916 PON device.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
---
 v2: Add interrupts and timeout-sec props
 v3: no change

 arch/arm64/boot/dts/qcom/pm8916.dtsi | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/pm8916.dtsi b/arch/arm64/boot/dts/qcom/pm8916.dtsi
index a05ebaf..3230b88 100644
--- a/arch/arm64/boot/dts/qcom/pm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/pm8916.dtsi
@@ -32,6 +32,12 @@
 				bias-pull-up;
 				linux,code = <KEY_POWER>;
 			};
+
+			watchdog {
+				compatible = "qcom,pm8916-wdt";
+				interrupts = <0x0 0x8 6 IRQ_TYPE_EDGE_RISING>;
+				timeout-sec = <60>;
+			};
 		};
 
 		pm8916_gpios: gpios@c000 {
-- 
2.7.4

Re: [v3,3/3] arm64: dts: qcom: pm8916: Add PON watchdog node

[Guenter Roeck]

On Fri, Nov 23, 2018 at 09:44:38AM +0100, Loic Poulain wrote:
> Add watchdog child node to the PM8916 PON device.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

Acked-by: Guenter Roeck <linux@roeck-us.net>

... with the assumption that this patch will be pushed through
an arm tree.

Guenter

> ---
>  v2: Add interrupts and timeout-sec props
>  v3: no change
> 
>  arch/arm64/boot/dts/qcom/pm8916.dtsi | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/pm8916.dtsi b/arch/arm64/boot/dts/qcom/pm8916.dtsi
> index a05ebaf..3230b88 100644
> --- a/arch/arm64/boot/dts/qcom/pm8916.dtsi
> +++ b/arch/arm64/boot/dts/qcom/pm8916.dtsi
> @@ -32,6 +32,12 @@
>  				bias-pull-up;
>  				linux,code = <KEY_POWER>;
>  			};
> +
> +			watchdog {
> +				compatible = "qcom,pm8916-wdt";
> +				interrupts = <0x0 0x8 6 IRQ_TYPE_EDGE_RISING>;
> +				timeout-sec = <60>;
> +			};
>  		};
>  
>  		pm8916_gpios: gpios@c000 {

Re: [PATCH v3 1/3] watchdog: Add pm8916 watchdog driver

[Guenter Roeck]

On 11/23/18 12:44 AM, Loic Poulain wrote:
> The PM816 module is a versatile PMIC with many diverse functions
> integrated, including, a watchdog.
> This watchdog is subcomponent of the PON (Power On) peripheral,
> in the same way as pwrkey/resin buttons.
> It works with two timers (2-stages), the first one generates an
> IRQ to the main SoC (APQ8016/MSM8916), the second one performs
> the reset.
> 
> This driver expects the following device hierarchy:
> [pm8916]->[pm8916-pon]->[pm8916-wdt]
> 
> It uses the pm8916 regmap to access PM8916 registers.
> 
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>   v2: SPDX license
>       headers ordering
>       coding styles / tabs / multi-line comments
>       pretimeout / bark interrupt
>       WDIOF_MAGICCLOSE flag
>       timeout init via fdt
>       devm usage
>   v3: Remove unused dev/irq variables from pm8916 wdt struct
> 
>   drivers/watchdog/Kconfig      |   8 ++
>   drivers/watchdog/Makefile     |   1 +
>   drivers/watchdog/pm8916_wdt.c | 211 ++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 220 insertions(+)
>   create mode 100644 drivers/watchdog/pm8916_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 2d64333..ef2c2b5 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -847,6 +847,14 @@ config SPRD_WATCHDOG
>   	  Say Y here to include watchdog timer supported
>   	  by Spreadtrum system.
>   
> +config PM8916_WATCHDOG
> +	tristate "QCOM PM8916 pmic watchdog"
> +	depends on OF && MFD_SPMI_PMIC
> +	select WATCHDOG_CORE
> +	help
> +	  Say Y here to include support watchdog timer embedded into the
> +	  pm8916 module.
> +
>   # X86 (i386 + ia64 + x86_64) Architecture
>   
>   config ACQUIRE_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index f69cdff..cc90e72 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -92,6 +92,7 @@ obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
>   obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
>   obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o
>   obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o
> +obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
>   
>   # X86 (i386 + ia64 + x86_64) Architecture
>   obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
> diff --git a/drivers/watchdog/pm8916_wdt.c b/drivers/watchdog/pm8916_wdt.c
> new file mode 100644
> index 0000000..7f10041
> --- /dev/null
> +++ b/drivers/watchdog/pm8916_wdt.c
> @@ -0,0 +1,211 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/bitops.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/property.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/watchdog.h>
> +
> +#define PON_INT_RT_STS			0x10
> +#define PMIC_WD_BARK_STS_BIT		BIT(6)
> +
> +#define PON_PMIC_WD_RESET_S1_TIMER	0x54
> +#define PON_PMIC_WD_RESET_S2_TIMER	0x55
> +
> +#define PON_PMIC_WD_RESET_S2_CTL	0x56
> +#define RESET_TYPE_WARM			0x01
> +#define RESET_TYPE_SHUTDOWN		0x04
> +#define RESET_TYPE_HARD			0x07
> +
> +#define PON_PMIC_WD_RESET_S2_CTL2	0x57
> +#define S2_RESET_EN_BIT			BIT(7)
> +
> +#define PON_PMIC_WD_RESET_PET		0x58
> +#define WATCHDOG_PET_BIT		BIT(0)
> +
> +#define PM8916_WDT_DEFAULT_TIMEOUT	32
> +#define PM8916_WDT_MIN_TIMEOUT		1
> +#define PM8916_WDT_MAX_TIMEOUT		127
> +
> +struct pm8916_wdt {
> +	struct regmap *regmap;
> +	struct watchdog_device wdev;
> +	u32 baseaddr;
> +};
> +
> +static int pm8916_wdt_start(struct watchdog_device *wdev)
> +{
> +	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
> +
> +	return regmap_update_bits(wdt->regmap,
> +				  wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
> +				  S2_RESET_EN_BIT, S2_RESET_EN_BIT);
> +}
> +
> +static int pm8916_wdt_stop(struct watchdog_device *wdev)
> +{
> +	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
> +
> +	return regmap_update_bits(wdt->regmap,
> +				  wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
> +				  S2_RESET_EN_BIT, 0);
> +}
> +
> +static int pm8916_wdt_ping(struct watchdog_device *wdev)
> +{
> +	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
> +
> +	return regmap_update_bits(wdt->regmap,
> +				  wdt->baseaddr + PON_PMIC_WD_RESET_PET,
> +				  WATCHDOG_PET_BIT, WATCHDOG_PET_BIT);
> +}
> +
> +static int pm8916_wdt_configure_timers(struct watchdog_device *wdev)
> +{
> +	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
> +	int err;
> +
> +	err = regmap_write(wdt->regmap,
> +			   wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,
> +			   wdev->timeout - wdev->pretimeout);
> +	if (err)
> +		return err;
> +
> +	return regmap_write(wdt->regmap,
> +			    wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,
> +			    wdev->pretimeout);
> +}
> +
> +static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,
> +				  unsigned int timeout)
> +{
> +	wdev->timeout = timeout;
> +
> +	return pm8916_wdt_configure_timers(wdev);
> +}
> +
> +static int pm8916_wdt_set_pretimeout(struct watchdog_device *wdev,
> +				     unsigned int pretimeout)
> +{
> +	wdev->pretimeout = pretimeout;
> +
> +	return pm8916_wdt_configure_timers(wdev);
> +}
> +
> +static irqreturn_t pm8916_wdt_isr(int irq, void *arg)
> +{
> +	struct pm8916_wdt *wdt = arg;
> +	int err, sts;
> +
> +	err = regmap_read(wdt->regmap, wdt->baseaddr + PON_INT_RT_STS, &sts);
> +	if (err)
> +		return IRQ_HANDLED;
> +
> +	if (sts & PMIC_WD_BARK_STS_BIT)
> +		watchdog_notify_pretimeout(&wdt->wdev);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static const struct watchdog_info pm8916_wdt_ident = {
> +	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
> +	.identity = "QCOM PM8916 PON WDT",
> +};
> +
> +static const struct watchdog_info pm8916_wdt_pt_ident = {
> +	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
> +		   WDIOF_PRETIMEOUT,
> +	.identity = "QCOM PM8916 PON WDT",
> +};
> +
> +static const struct watchdog_ops pm8916_wdt_ops = {
> +	.owner = THIS_MODULE,
> +	.start = pm8916_wdt_start,
> +	.stop = pm8916_wdt_stop,
> +	.ping = pm8916_wdt_ping,
> +	.set_timeout = pm8916_wdt_set_timeout,
> +	.set_pretimeout = pm8916_wdt_set_pretimeout,
> +};
> +
> +static int pm8916_wdt_probe(struct platform_device *pdev)
> +{
> +	struct pm8916_wdt *wdt;
> +	struct device *parent;
> +	int err, irq;
> +
> +	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> +	if (!wdt)
> +		return -ENOMEM;
> +
> +	parent = pdev->dev.parent;
> +
> +	/*
> +	 * The pm8916-pon-wdt is a child of the pon device, which is a child
> +	 * of the pm8916 mfd device. We want access to the pm8916 registers.
> +	 * Retrieve regmap from pm8916 (parent->parent) and base address
> +	 * from pm8916-pon (pon).
> +	 */
> +	wdt->regmap = dev_get_regmap(parent->parent, NULL);
> +	if (!wdt->regmap) {
> +		dev_err(&pdev->dev, "failed to locate regmap\n");
> +		return -ENODEV;
> +	}
> +
> +	err = device_property_read_u32(parent, "reg", &wdt->baseaddr);
> +	if (err) {
> +		dev_err(&pdev->dev, "failed to get pm8916-pon address\n");
> +		return err;
> +	}
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq > 0) {
> +		if (devm_request_irq(&pdev->dev, irq, pm8916_wdt_isr, 0,
> +				     "pm8916_wdt", wdt))
> +			irq = 0;
> +	}
> +
> +	/* Configure watchdog to hard-reset mode */
> +	err = regmap_write(wdt->regmap,
> +			   wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL,
> +			   RESET_TYPE_HARD);
> +	if (err) {
> +		dev_err(&pdev->dev, "failed configure watchdog\n");
> +		return err;
> +	}
> +
> +	wdt->wdev.info = (irq > 0) ? &pm8916_wdt_pt_ident : &pm8916_wdt_ident,
> +	wdt->wdev.ops = &pm8916_wdt_ops,
> +	wdt->wdev.parent = &pdev->dev;
> +	wdt->wdev.min_timeout = PM8916_WDT_MIN_TIMEOUT;
> +	wdt->wdev.max_timeout = PM8916_WDT_MAX_TIMEOUT;
> +	wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;
> +	wdt->wdev.pretimeout = 0;
> +	watchdog_set_drvdata(&wdt->wdev, wdt);
> +
> +	watchdog_init_timeout(&wdt->wdev, 0, &pdev->dev);
> +	pm8916_wdt_configure_timers(&wdt->wdev);
> +
> +	return devm_watchdog_register_device(&pdev->dev, &wdt->wdev);
> +}
> +
> +static const struct of_device_id pm8916_wdt_id_table[] = {
> +	{ .compatible = "qcom,pm8916-wdt" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, pm8916_wdt_id_table);
> +
> +static struct platform_driver pm8916_wdt_driver = {
> +	.probe = pm8916_wdt_probe,
> +	.driver = {
> +		.name = "pm8916-wdt",
> +		.of_match_table = of_match_ptr(pm8916_wdt_id_table),
> +	},
> +};
> +module_platform_driver(pm8916_wdt_driver);
> +
> +MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
> +MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
> +MODULE_LICENSE("GPL v2");
>