[1/3] watchdog: Add pm8916 watchdog driver

Message ID 1542443319-23369-1-git-send-email-loic.poulain@linaro.org
State New
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  • [1/3] watchdog: Add pm8916 watchdog driver
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Commit Message

Loic Poulain Nov. 17, 2018, 8:28 a.m.
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 hierachy:
[pm8916]->[pm8916-pon]->[pm8916-wdt]

It uses the pm8916 regmap to access PM8916 registers.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

---
 drivers/watchdog/Kconfig      |   8 ++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/pm8916_wdt.c | 177 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 186 insertions(+)
 create mode 100644 drivers/watchdog/pm8916_wdt.c

-- 
2.7.4

Comments

Guenter Roeck Nov. 19, 2018, 9:23 p.m. | #1
On Sat, Nov 17, 2018 at 09:28:37AM +0100, 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 hierachy:

> [pm8916]->[pm8916-pon]->[pm8916-wdt]

> 

> It uses the pm8916 regmap to access PM8916 registers.

> 

> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

> ---

>  drivers/watchdog/Kconfig      |   8 ++

>  drivers/watchdog/Makefile     |   1 +

>  drivers/watchdog/pm8916_wdt.c | 177 ++++++++++++++++++++++++++++++++++++++++++

>  3 files changed, 186 insertions(+)

>  create mode 100644 drivers/watchdog/pm8916_wdt.c

> 

> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig

> index 2d64333..66bab61 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..36f9763

> --- /dev/null

> +++ b/drivers/watchdog/pm8916_wdt.c

> @@ -0,0 +1,177 @@

> +/*

> + * Watchdog driver for QCOM PM8916

> + *

> + * Copyright (C) 2018 Loic Poulain, Linaro <loic.poulain@linaro.org>

> + *

> + * This program is free software; you can redistribute it and/or modify

> + * it under the terms of the GNU General Public License version 2 and

> + * only 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.


Please use the SPDX license identifier.

> + */

> +

> +#include <linux/bitops.h>

> +#include <linux/kernel.h>

> +#include <linux/module.h>

> +#include <linux/of.h>

> +#include <linux/property.h>

> +#include <linux/platform_device.h>

> +#include <linux/watchdog.h>

> +#include <linux/regmap.h>

> +

Aplhabetic order, please.

> +#define PM8916_WDT_DEFAULT_TIMEOUT 32

> +

> +#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 PON_PMIC_WD_RESET_S2_CTL2	0x57

> +#define PON_PMIC_WD_RESET_PET		0x58

> +

> +#define S2_RESET_EN_MASK BIT(7)

> +#define S2_RESET_EN (1 << 7)


Please use tabs. Also, why (1 << 7) instead of BIT(7) ?

Overall, since this is a single bit, having both EN_MASK and EN
seems unnecessary, but if you do,

> +

> +#define WATCHDOG_PET_MASK BIT(0)

> +


please do the same here.

> +struct pm8916_wdt {

> +	struct device *dev;

> +	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_MASK, S2_RESET_EN);

> +}

> +

> +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_MASK, 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_MASK, 1);


The "1" is really supposed to be BIT(0).

> +}

> +

> +static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,

> +				  unsigned int timeout)

> +{

> +	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);

> +	int err;

> +

> +	wdev->timeout = timeout;

> +

> +	/* This is a two stages watchdog, set stage-1 timer generate an irq and


Please use standard multi-line comments.

> +	 * stage-2 trigger the reset. In order to respect expected timeout, set

> +	 * stage-1 timer to timeout and stage-2 to 0.

> +	 */

> +	err = regmap_write(wdt->regmap,

> +			   wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,

> +			   timeout);

> +	if (err)

> +		return err;

> +

> +	return regmap_write(wdt->regmap,

> +			    wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,

> +			    0);


The watchdog subsystem does support pretimeout, which seems to match the
description here. Not mandatory to support it, but it might make sense.

> +}

> +

> +static const struct watchdog_info pm8916_wdt_ident = {

> +	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,


No WDIOF_MAGICCLOSE ?

> +	.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,

> +};

> +

> +static int pm8916_wdt_probe(struct platform_device *pdev)

> +{

> +	struct pm8916_wdt *wdt;

> +	struct device *parent;

> +	int err;

> +

> +	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);

> +	if (!wdt)

> +		return -ENOMEM;

> +

> +	wdt->dev = &pdev->dev;

> +	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 address\n");


... and the user will wonder "what address" 

> +		return err;

> +	}

> +

> +	/* Configure watchdog to hard-reset mode */

> +	err = regmap_write(wdt->regmap,

> +			   wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL, 0x07);


This is where symbolic defines come in handy, even if used only once.

> +	if (err) {

> +		dev_err(&pdev->dev, "failed configure watchdog\n");

> +		return err;

> +	}

> +

> +	wdt->wdev.info = &pm8916_wdt_ident,

> +	wdt->wdev.ops = &pm8916_wdt_ops,

> +	wdt->wdev.parent = &pdev->dev;

> +	wdt->wdev.min_timeout = 1;

> +	wdt->wdev.max_timeout = 127;


Is this the real range supported by the hardware ?

> +	wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;

> +	watchdog_set_drvdata(&wdt->wdev, wdt);

> +

> +	pm8916_wdt_set_timeout(&wdt->wdev, wdt->wdev.timeout);

> +

Is timeout initialization via fdt not supported on purpose ?

> +	return watchdog_register_device(&wdt->wdev);


devm_watchdog_register_device(), or driver removal may result in an
unpleasant surprise.

> +}

> +

> +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

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 2d64333..66bab61 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..36f9763
--- /dev/null
+++ b/drivers/watchdog/pm8916_wdt.c
@@ -0,0 +1,177 @@ 
+/*
+ * Watchdog driver for QCOM PM8916
+ *
+ * Copyright (C) 2018 Loic Poulain, Linaro <loic.poulain@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/regmap.h>
+
+#define PM8916_WDT_DEFAULT_TIMEOUT 32
+
+#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 PON_PMIC_WD_RESET_S2_CTL2	0x57
+#define PON_PMIC_WD_RESET_PET		0x58
+
+#define S2_RESET_EN_MASK BIT(7)
+#define S2_RESET_EN (1 << 7)
+
+#define WATCHDOG_PET_MASK BIT(0)
+
+struct pm8916_wdt {
+	struct device *dev;
+	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_MASK, S2_RESET_EN);
+}
+
+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_MASK, 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_MASK, 1);
+}
+
+static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,
+				  unsigned int timeout)
+{
+	struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+	int err;
+
+	wdev->timeout = timeout;
+
+	/* This is a two stages watchdog, set stage-1 timer generate an irq and
+	 * stage-2 trigger the reset. In order to respect expected timeout, set
+	 * stage-1 timer to timeout and stage-2 to 0.
+	 */
+	err = regmap_write(wdt->regmap,
+			   wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,
+			   timeout);
+	if (err)
+		return err;
+
+	return regmap_write(wdt->regmap,
+			    wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,
+			    0);
+}
+
+static const struct watchdog_info pm8916_wdt_ident = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	.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,
+};
+
+static int pm8916_wdt_probe(struct platform_device *pdev)
+{
+	struct pm8916_wdt *wdt;
+	struct device *parent;
+	int err;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->dev = &pdev->dev;
+	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 address\n");
+		return err;
+	}
+
+	/* Configure watchdog to hard-reset mode */
+	err = regmap_write(wdt->regmap,
+			   wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL, 0x07);
+	if (err) {
+		dev_err(&pdev->dev, "failed configure watchdog\n");
+		return err;
+	}
+
+	wdt->wdev.info = &pm8916_wdt_ident,
+	wdt->wdev.ops = &pm8916_wdt_ops,
+	wdt->wdev.parent = &pdev->dev;
+	wdt->wdev.min_timeout = 1;
+	wdt->wdev.max_timeout = 127;
+	wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;
+	watchdog_set_drvdata(&wdt->wdev, wdt);
+
+	pm8916_wdt_set_timeout(&wdt->wdev, wdt->wdev.timeout);
+
+	return watchdog_register_device(&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");