| Message ID | 1385798072-3886-1-git-send-email-shc_work@mail.ru |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 11/29/2013 11:54 PM, Alexander Shiyan wrote: > This patch adds a watchdog driver for devices controlled through GPIO, > (Analog Devices ADM706, Maxim MAX823, National NE555 etc). > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > --- Looks pretty good, except for a single nitpick below (sorry I didn't notice that one earlier). Also, as mentioned before, a changelog describing what changed and what didn't would be really helpful. Thanks, Guenter > .../devicetree/bindings/watchdog/gpio-wdt.txt | 23 ++ > drivers/watchdog/Kconfig | 8 + > drivers/watchdog/Makefile | 1 + > drivers/watchdog/gpio_wdt.c | 254 +++++++++++++++++++++ > 4 files changed, 286 insertions(+) > create mode 100644 Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > create mode 100644 drivers/watchdog/gpio_wdt.c > > diff --git a/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > new file mode 100644 > index 0000000..37afec1 > --- /dev/null > +++ b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > @@ -0,0 +1,23 @@ > +* GPIO-controlled Watchdog > + > +Required Properties: > +- compatible: Should contain "linux,wdt-gpio". > +- gpios: From common gpio binding; gpio connection to WDT reset pin. > +- hw_algo: The algorithm used by the driver. Should be one of the > + following values: > + - toggle: Either a high-to-low or a low-to-high transition clears > + the WDT counter. The watchdog timer is disabled when GPIO is > + left floating or connected to a three-state buffer. > + - level: Low or high level starts counting WDT timeout, > + the opposite level disables the WDT. Active level is determined > + by the GPIO flags. > +- hw_margin_ms: Maximum time to reset watchdog circuit (milliseconds). > + > +Example: > + watchdog: watchdog { > + /* ADM706 */ > + compatible = "linux,wdt-gpio"; > + gpios = <&gpio3 9 GPIO_ACTIVE_LOW>; > + hw_algo = "toggle"; > + hw_margin_ms = <1600>; Last call for comments from devicetree maintainers ... > + }; > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 5be6e91..968a882 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -87,6 +87,14 @@ config DA9055_WATCHDOG > This driver can also be built as a module. If so, the module > will be called da9055_wdt. > > +config GPIO_WATCHDOG > + tristate "Watchdog device controlled through GPIO-line" > + depends on OF_GPIO > + select WATCHDOG_CORE > + help > + If you say yes here you get support for watchdog device > + controlled through GPIO-line. > + > config WM831X_WATCHDOG > tristate "WM831x watchdog" > depends on MFD_WM831X > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 91bd95a..dc17275 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -171,6 +171,7 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o > # Architecture Independent > obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o > obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o > +obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o > obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o > obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o > obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o > diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c > new file mode 100644 > index 0000000..1e02dd6 > --- /dev/null > +++ b/drivers/watchdog/gpio_wdt.c > @@ -0,0 +1,254 @@ > +/* > + * Driver for watchdog device controlled through GPIO-line > + * > + * Author: 2013, Alexander Shiyan <shc_work@mail.ru> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License as published by > + * the Free Software Foundation; either version 2 of the License, or > + * (at your option) any later version. > + */ > + > +#include <linux/err.h> > +#include <linux/delay.h> > +#include <linux/module.h> > +#include <linux/notifier.h> > +#include <linux/of_gpio.h> > +#include <linux/platform_device.h> > +#include <linux/reboot.h> > +#include <linux/watchdog.h> > + > +#define SOFT_TIMEOUT_MIN 1 > +#define SOFT_TIMEOUT_DEF 60 > +#define SOFT_TIMEOUT_MAX 0xffff > + > +enum { > + HW_ALGO_TOGGLE, > + HW_ALGO_LEVEL, > +}; > + > +struct gpio_wdt_priv { > + int gpio; > + bool active_low; > + bool state; > + unsigned int hw_algo; > + unsigned int hw_margin; > + unsigned long last_jiffies; > + struct notifier_block notifier; > + struct timer_list timer; > + struct watchdog_device wdd; > +}; > + > +static void gpio_wdt_disable(struct gpio_wdt_priv *priv) > +{ > + gpio_set_value_cansleep(priv->gpio, !priv->active_low); > + > + /* Put GPIO back to tristate */ > + if (priv->hw_algo == HW_ALGO_TOGGLE) > + gpio_direction_input(priv->gpio); > +} > + > +static int gpio_wdt_start(struct watchdog_device *wdd) > +{ > + struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); > + > + priv->state = priv->active_low; > + gpio_direction_output(priv->gpio, priv->state); > + priv->last_jiffies = jiffies; > + mod_timer(&priv->timer, priv->last_jiffies + priv->hw_margin); > + > + return 0; > +} > + > +static int gpio_wdt_stop(struct watchdog_device *wdd) > +{ > + struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); > + > + mod_timer(&priv->timer, 0); > + gpio_wdt_disable(priv); > + > + 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 void gpio_wdt_hwping(unsigned long data) > +{ > + struct watchdog_device *wdd = (struct watchdog_device *)data; > + struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); > + > + if (time_after(jiffies, priv->last_jiffies + > + msecs_to_jiffies(wdd->timeout * 1000))) { > + dev_crit(wdd->dev, "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 */ > + priv->state = !priv->state; > + gpio_set_value_cansleep(priv->gpio, priv->state); > + break; > + case HW_ALGO_LEVEL: > + /* Pulse */ > + gpio_set_value_cansleep(priv->gpio, !priv->active_low); > + udelay(1); > + gpio_set_value_cansleep(priv->gpio, priv->active_low); > + break; > + } > +} > + > +static int gpio_wdt_notify_sys(struct notifier_block *nb, unsigned long code, > + void *unused) > +{ > + struct gpio_wdt_priv *priv = container_of(nb, struct gpio_wdt_priv, > + notifier); > + > + mod_timer(&priv->timer, 0); > + > + switch (code) { > + case SYS_HALT: > + case SYS_POWER_OFF: > + gpio_wdt_disable(priv); > + break; > + default: > + break; > + } > + > + return NOTIFY_DONE; > +} > + > +static const struct watchdog_info gpio_wdt_ident = { > + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | > + WDIOF_SETTIMEOUT, > + .identity = "GPIO Watchdog", > +}; > + > +static const struct watchdog_ops gpio_wdt_ops = { > + .owner = THIS_MODULE, > + .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) > +{ > + struct gpio_wdt_priv *priv; > + enum of_gpio_flags flags; > + unsigned int hw_margin; > + unsigned long f = 0; > + const char *algo; > + int ret; > + > + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + priv->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags); > + if (!gpio_is_valid(priv->gpio)) > + return priv->gpio; > + > + priv->active_low = flags & OF_GPIO_ACTIVE_LOW; > + > + ret = of_property_read_string(pdev->dev.of_node, "hw_algo", &algo); > + if (ret) > + return ret; > + if (!strncmp(algo, "toggle", 6)) { > + priv->hw_algo = HW_ALGO_TOGGLE; > + f = GPIOF_IN; > + } else if (!strncmp(algo, "level", 5)) { > + priv->hw_algo = HW_ALGO_LEVEL; > + f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; > + } else { > + return -EINVAL; > + } > + > + ret = devm_gpio_request_one(&pdev->dev, priv->gpio, f, > + dev_name(&pdev->dev)); > + if (ret) > + return ret; > + > + ret = of_property_read_u32(pdev->dev.of_node, > + "hw_margin_ms", &hw_margin); > + if (ret) > + return ret; > + /* Disallow values lower than 2 and higher than 65535 ms */ > + if ((hw_margin < 2) || (hw_margin > 65535)) Unnecessary ( ). > + return -EINVAL; > + > + /* Use safe value (1/2 of real timeout) */ > + priv->hw_margin = msecs_to_jiffies(hw_margin / 2); > + > + watchdog_set_drvdata(&priv->wdd, priv); > + > + 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; > + > + 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); > + > + ret = watchdog_register_device(&priv->wdd); > + if (ret) > + return ret; > + > + priv->notifier.notifier_call = gpio_wdt_notify_sys; > + ret = register_reboot_notifier(&priv->notifier); > + if (ret) > + watchdog_unregister_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); > + unregister_reboot_notifier(&priv->notifier); > + watchdog_unregister_device(&priv->wdd); > + > + return 0; > +} > + > +static const struct of_device_id gpio_wdt_dt_ids[] = { > + { .compatible = "linux,wdt-gpio", }, > + { } > +}; > +MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids); > + > +static struct platform_driver gpio_wdt_driver = { > + .driver = { > + .name = "gpio-wdt", > + .owner = THIS_MODULE, > + .of_match_table = gpio_wdt_dt_ids, > + }, > + .probe = gpio_wdt_probe, > + .remove = gpio_wdt_remove, > +}; > +module_platform_driver(gpio_wdt_driver); > + > +MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); > +MODULE_DESCRIPTION("GPIO Watchdog"); > +MODULE_LICENSE("GPL"); > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hello. > On 11/29/2013 11:54 PM, Alexander Shiyan wrote: > > This patch adds a watchdog driver for devices controlled through GPIO, > > (Analog Devices ADM706, Maxim MAX823, National NE555 etc). > > > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > > --- > > Looks pretty good, except for a single nitpick below (sorry I didn't notice that one earlier). > > Also, as mentioned before, a changelog describing what changed and what didn't > would be really helpful. Just fixed all observations made by you earlier. ... > > + /* Disallow values lower than 2 and higher than 65535 ms */ > > + if ((hw_margin < 2) || (hw_margin > 65535)) > > Unnecessary ( ). This can be corrected during merge. Isn't it? Or you expect v4? Thanks. ---
On Sun, Dec 01, 2013 at 11:03:27PM +0400, Alexander Shiyan wrote: > Hello. > > > On 11/29/2013 11:54 PM, Alexander Shiyan wrote: > > > This patch adds a watchdog driver for devices controlled through GPIO, > > > (Analog Devices ADM706, Maxim MAX823, National NE555 etc). > > > > > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > > > --- > > > > Looks pretty good, except for a single nitpick below (sorry I didn't notice that one earlier). > > > > Also, as mentioned before, a changelog describing what changed and what didn't > > would be really helpful. > > Just fixed all observations made by you earlier. > Yes, but since you did not say that, I had to look up my earlier comments and check against this version. This takes time, and time is one thing which reviewers or subsystem maintainers don't always have readily available. > ... > > > + /* Disallow values lower than 2 and higher than 65535 ms */ > > > + if ((hw_margin < 2) || (hw_margin > 65535)) > > > > Unnecessary ( ). > > This can be corrected during merge. Isn't it? Or you expect v4? > If I were the watchdog maintainer, yes. Since I am not, it really depends on Wim. He might accept your patch as-is, make the change himself, expect you to submit another version, or request additional changes. You'll see. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, 30 Nov 2013 11:54:32 +0400 Alexander Shiyan <shc_work@mail.ru> wrote: > This patch adds a watchdog driver for devices controlled through GPIO, > (Analog Devices ADM706, Maxim MAX823, National NE555 etc). > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > --- > .../devicetree/bindings/watchdog/gpio-wdt.txt | 23 ++ > drivers/watchdog/Kconfig | 8 + > drivers/watchdog/Makefile | 1 + > drivers/watchdog/gpio_wdt.c | 254 +++++++++++++++++++++ > 4 files changed, 286 insertions(+) > create mode 100644 Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > create mode 100644 drivers/watchdog/gpio_wdt.c ... Ping.
On 12/06/2013 10:52 PM, Alexander Shiyan wrote: > On Sat, 30 Nov 2013 11:54:32 +0400 > Alexander Shiyan <shc_work@mail.ru> wrote: > >> This patch adds a watchdog driver for devices controlled through GPIO, >> (Analog Devices ADM706, Maxim MAX823, National NE555 etc). >> >> Signed-off-by: Alexander Shiyan <shc_work@mail.ru> >> --- >> .../devicetree/bindings/watchdog/gpio-wdt.txt | 23 ++ >> drivers/watchdog/Kconfig | 8 + >> drivers/watchdog/Makefile | 1 + >> drivers/watchdog/gpio_wdt.c | 254 +++++++++++++++++++++ >> 4 files changed, 286 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/watchdog/gpio-wdt.txt >> create mode 100644 drivers/watchdog/gpio_wdt.c > ... > > Ping. > Wim typically only finds the time to look at pending patches a couple of weeks before the next commit window opens. I'll send him a reminder with all patches I am aware of in a week or so. I have this one in my list. Guenter -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Alexander, > > > + /* Disallow values lower than 2 and higher than 65535 ms */ > > > + if ((hw_margin < 2) || (hw_margin > 65535)) > > > > Unnecessary ( ). > > This can be corrected during merge. Isn't it? Or you expect v4? Yes, can be corrected during merge window, so no v4 expected. Kind regards, Wim. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Alexander, > This patch adds a watchdog driver for devices controlled through GPIO, > (Analog Devices ADM706, Maxim MAX823, National NE555 etc). > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > --- > .../devicetree/bindings/watchdog/gpio-wdt.txt | 23 ++ > drivers/watchdog/Kconfig | 8 + > drivers/watchdog/Makefile | 1 + > drivers/watchdog/gpio_wdt.c | 254 +++++++++++++++++++++ > 4 files changed, 286 insertions(+) > create mode 100644 Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > create mode 100644 drivers/watchdog/gpio_wdt.c Patch added to linux-watchdog-next. Kind regards, Wim. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt new file mode 100644 index 0000000..37afec1 --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt @@ -0,0 +1,23 @@ +* GPIO-controlled Watchdog + +Required Properties: +- compatible: Should contain "linux,wdt-gpio". +- gpios: From common gpio binding; gpio connection to WDT reset pin. +- hw_algo: The algorithm used by the driver. Should be one of the + following values: + - toggle: Either a high-to-low or a low-to-high transition clears + the WDT counter. The watchdog timer is disabled when GPIO is + left floating or connected to a three-state buffer. + - level: Low or high level starts counting WDT timeout, + the opposite level disables the WDT. Active level is determined + by the GPIO flags. +- hw_margin_ms: Maximum time to reset watchdog circuit (milliseconds). + +Example: + watchdog: watchdog { + /* ADM706 */ + compatible = "linux,wdt-gpio"; + gpios = <&gpio3 9 GPIO_ACTIVE_LOW>; + hw_algo = "toggle"; + hw_margin_ms = <1600>; + }; diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 5be6e91..968a882 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -87,6 +87,14 @@ config DA9055_WATCHDOG This driver can also be built as a module. If so, the module will be called da9055_wdt. +config GPIO_WATCHDOG + tristate "Watchdog device controlled through GPIO-line" + depends on OF_GPIO + select WATCHDOG_CORE + help + If you say yes here you get support for watchdog device + controlled through GPIO-line. + config WM831X_WATCHDOG tristate "WM831x watchdog" depends on MFD_WM831X diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 91bd95a..dc17275 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -171,6 +171,7 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o # Architecture Independent obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o +obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c new file mode 100644 index 0000000..1e02dd6 --- /dev/null +++ b/drivers/watchdog/gpio_wdt.c @@ -0,0 +1,254 @@ +/* + * Driver for watchdog device controlled through GPIO-line + * + * Author: 2013, Alexander Shiyan <shc_work@mail.ru> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/err.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/notifier.h> +#include <linux/of_gpio.h> +#include <linux/platform_device.h> +#include <linux/reboot.h> +#include <linux/watchdog.h> + +#define SOFT_TIMEOUT_MIN 1 +#define SOFT_TIMEOUT_DEF 60 +#define SOFT_TIMEOUT_MAX 0xffff + +enum { + HW_ALGO_TOGGLE, + HW_ALGO_LEVEL, +}; + +struct gpio_wdt_priv { + int gpio; + bool active_low; + bool state; + unsigned int hw_algo; + unsigned int hw_margin; + unsigned long last_jiffies; + struct notifier_block notifier; + struct timer_list timer; + struct watchdog_device wdd; +}; + +static void gpio_wdt_disable(struct gpio_wdt_priv *priv) +{ + gpio_set_value_cansleep(priv->gpio, !priv->active_low); + + /* Put GPIO back to tristate */ + if (priv->hw_algo == HW_ALGO_TOGGLE) + gpio_direction_input(priv->gpio); +} + +static int gpio_wdt_start(struct watchdog_device *wdd) +{ + struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); + + priv->state = priv->active_low; + gpio_direction_output(priv->gpio, priv->state); + priv->last_jiffies = jiffies; + mod_timer(&priv->timer, priv->last_jiffies + priv->hw_margin); + + return 0; +} + +static int gpio_wdt_stop(struct watchdog_device *wdd) +{ + struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); + + mod_timer(&priv->timer, 0); + gpio_wdt_disable(priv); + + 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 void gpio_wdt_hwping(unsigned long data) +{ + struct watchdog_device *wdd = (struct watchdog_device *)data; + struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd); + + if (time_after(jiffies, priv->last_jiffies + + msecs_to_jiffies(wdd->timeout * 1000))) { + dev_crit(wdd->dev, "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 */ + priv->state = !priv->state; + gpio_set_value_cansleep(priv->gpio, priv->state); + break; + case HW_ALGO_LEVEL: + /* Pulse */ + gpio_set_value_cansleep(priv->gpio, !priv->active_low); + udelay(1); + gpio_set_value_cansleep(priv->gpio, priv->active_low); + break; + } +} + +static int gpio_wdt_notify_sys(struct notifier_block *nb, unsigned long code, + void *unused) +{ + struct gpio_wdt_priv *priv = container_of(nb, struct gpio_wdt_priv, + notifier); + + mod_timer(&priv->timer, 0); + + switch (code) { + case SYS_HALT: + case SYS_POWER_OFF: + gpio_wdt_disable(priv); + break; + default: + break; + } + + return NOTIFY_DONE; +} + +static const struct watchdog_info gpio_wdt_ident = { + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | + WDIOF_SETTIMEOUT, + .identity = "GPIO Watchdog", +}; + +static const struct watchdog_ops gpio_wdt_ops = { + .owner = THIS_MODULE, + .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) +{ + struct gpio_wdt_priv *priv; + enum of_gpio_flags flags; + unsigned int hw_margin; + unsigned long f = 0; + const char *algo; + int ret; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags); + if (!gpio_is_valid(priv->gpio)) + return priv->gpio; + + priv->active_low = flags & OF_GPIO_ACTIVE_LOW; + + ret = of_property_read_string(pdev->dev.of_node, "hw_algo", &algo); + if (ret) + return ret; + if (!strncmp(algo, "toggle", 6)) { + priv->hw_algo = HW_ALGO_TOGGLE; + f = GPIOF_IN; + } else if (!strncmp(algo, "level", 5)) { + priv->hw_algo = HW_ALGO_LEVEL; + f = priv->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; + } else { + return -EINVAL; + } + + ret = devm_gpio_request_one(&pdev->dev, priv->gpio, f, + dev_name(&pdev->dev)); + if (ret) + return ret; + + ret = of_property_read_u32(pdev->dev.of_node, + "hw_margin_ms", &hw_margin); + if (ret) + return ret; + /* Disallow values lower than 2 and higher than 65535 ms */ + 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); + + watchdog_set_drvdata(&priv->wdd, priv); + + 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; + + 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); + + ret = watchdog_register_device(&priv->wdd); + if (ret) + return ret; + + priv->notifier.notifier_call = gpio_wdt_notify_sys; + ret = register_reboot_notifier(&priv->notifier); + if (ret) + watchdog_unregister_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); + unregister_reboot_notifier(&priv->notifier); + watchdog_unregister_device(&priv->wdd); + + return 0; +} + +static const struct of_device_id gpio_wdt_dt_ids[] = { + { .compatible = "linux,wdt-gpio", }, + { } +}; +MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids); + +static struct platform_driver gpio_wdt_driver = { + .driver = { + .name = "gpio-wdt", + .owner = THIS_MODULE, + .of_match_table = gpio_wdt_dt_ids, + }, + .probe = gpio_wdt_probe, + .remove = gpio_wdt_remove, +}; +module_platform_driver(gpio_wdt_driver); + +MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>"); +MODULE_DESCRIPTION("GPIO Watchdog"); +MODULE_LICENSE("GPL");
This patch adds a watchdog driver for devices controlled through GPIO, (Analog Devices ADM706, Maxim MAX823, National NE555 etc). Signed-off-by: Alexander Shiyan <shc_work@mail.ru> --- .../devicetree/bindings/watchdog/gpio-wdt.txt | 23 ++ drivers/watchdog/Kconfig | 8 + drivers/watchdog/Makefile | 1 + drivers/watchdog/gpio_wdt.c | 254 +++++++++++++++++++++ 4 files changed, 286 insertions(+) create mode 100644 Documentation/devicetree/bindings/watchdog/gpio-wdt.txt create mode 100644 drivers/watchdog/gpio_wdt.c