Message ID | 1385483188-12221-1-git-send-email-shc_work@mail.ru |
---|---|
State | Accepted, archived |
Headers | show |
On 11/26/2013 08:26 AM, Alexander Shiyan wrote: > This patch adds a watchdog driver for devices controlled through GPIO, > (Analog Devices ADM706, IC 555 etc). > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > --- A list of changes since v1 would be helpful. > .../devicetree/bindings/watchdog/gpio-wdt.txt | 23 ++ > drivers/watchdog/Kconfig | 8 + > drivers/watchdog/Makefile | 1 + > drivers/watchdog/gpio_wdt.c | 246 +++++++++++++++++++++ > 4 files changed, 278 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..08ba8e5 > --- /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". Should ? > +- gpios: From common gpio binding; gpio connection to WDT reset pin. > +- wdt-gpio,hw_algo: The algorithm used by the driver. Should be one > + of the following values: Should ? > + - 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. > +- wdt-gpio,hw_margin_ms: Maximum time to reset watchdog circuit (milliseconds). > + > +Example: > + watchdog: watchdog { > + /* ADM706 */ > + compatible = "linux,wdt-gpio"; Oddly enough, the bindings could be used by non-Linux operating systems, but who am I to argue. Fine if this is what the DT maintainers want to see. > + gpios = <&gpio3 9 GPIO_ACTIVE_LOW>; > + wdt-gpio,hw_algo = "toggle"; > + wdt-gpio,hw_margin_ms = <1600>; Is this a new means to name device specific properties ? "wdt-gpio" in those bindings is quite redundant with "wdt-gpio" in the compatible property. Again, though, who am I to argue. > + }; > 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..c7166be > --- /dev/null > +++ b/drivers/watchdog/gpio_wdt.c > @@ -0,0 +1,246 @@ > +/* > + * 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 int 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) > + return gpio_direction_input(priv->gpio); > + No disable for 'level' watchdogs ? Shouldn't it be set to the opposite of priv->state ? > + return 0; Since this is an internal function which never returns anything but 0, you might as well make it void. > +} > + > +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); > + > + return gpio_wdt_disable(priv); > +} > + > +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 0; > +} > + > +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_before(jiffies, priv->last_jiffies + > + msecs_to_jiffies(wdd->timeout * 1000))) { > + /* 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); Pretty arbitrary toggle time. Should this be a property ? > + gpio_set_value_cansleep(priv->gpio, priv->active_low); > + break; > + } > + } else > + dev_crit(wdd->dev, "Timer expired. System will reboot soon!\n"); Coding style (chapter 3): else should be in { } too. > +} > + > +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; > + case SYS_DOWN: This case statement is unnecessary. > + 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; > + const __be32 *prp; > + u32 hw_margin; > + 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); > + !! is unnecessary for assignments to booleans. > + ret = devm_gpio_request_one(&pdev->dev, priv->gpio, GPIOF_IN, > + dev_name(&pdev->dev)); > + if (ret) > + return ret; > + > + prp = of_get_property(pdev->dev.of_node, "wdt-gpio,hw_algo", NULL); > + if (!prp) > + return -EINVAL; I am a bit concerned about using of_get_property() to read a string. If the provided property is an integer, one can only hope that nothing odd happens. How about using of_property_read_string() instead ? That would at least provide some protection. > + if (!strncmp((const char *)prp, "toggle", 6)) > + priv->hw_algo = HW_ALGO_TOGGLE; > + else if (!strncmp((const char *)prp, "level", 5)) > + priv->hw_algo = HW_ALGO_LEVEL; > + else > + return -ENOTSUPP; This suggests that the value is valid but not supported. -EINVAL may be better. > + > + prp = of_get_property(pdev->dev.of_node, "wdt-gpio,hw_margin_ms", NULL); > + if (!prp) > + return -EINVAL; There is also of_property_read_u32(). > + hw_margin = be32_to_cpu(*prp); > + /* Disallow values lower than 2 and higher than 65535 ms */ > + if ((hw_margin < 2) || (hw_margin > 65535)) > + return -EINVAL; > + > + /* Use safe value (2/3 of real timeout) */ > + priv->hw_margin = msecs_to_jiffies(hw_margin * 2 / 3); > + Hope this is safe enough. I would have used 1/2, but that is really up to you to decide. > + 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); > + > + priv->notifier.notifier_call = gpio_wdt_notify_sys; > + ret = register_reboot_notifier(&priv->notifier); > + if (ret) > + return ret; > + > + return watchdog_register_device(&priv->wdd); If this fails you don't call unregister_reboot_notifier. > +} > + > +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 11/26/2013 08:26 AM, Alexander Shiyan wrote: > > This patch adds a watchdog driver for devices controlled through GPIO, > > (Analog Devices ADM706, IC 555 etc). > > > > Signed-off-by: Alexander Shiyan <shc_work@mail.ru> ... > > +++ b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt > > @@ -0,0 +1,23 @@ > > +* GPIO-controlled Watchdog > > + > > +Required Properties: > > +- compatible: Should contain "linux,wdt-gpio". > > Should ? > > > +- gpios: From common gpio binding; gpio connection to WDT reset pin. > > +- wdt-gpio,hw_algo: The algorithm used by the driver. Should be one > > + of the following values: > > Should ? What wrong here? ... > > +Example: > > + watchdog: watchdog { > > + /* ADM706 */ > > + compatible = "linux,wdt-gpio"; > > Oddly enough, the bindings could be used by non-Linux operating systems, > but who am I to argue. Fine if this is what the DT maintainers want to see. On my opinion this mean that this is not a real hardware, but hardware emulation, like some other driver does. ... > > diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c > > new file mode 100644 > > index 0000000..c7166be > > --- /dev/null > > +++ b/drivers/watchdog/gpio_wdt.c > > @@ -0,0 +1,246 @@ > > +/* > > + * 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 int 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) > > + return gpio_direction_input(priv->gpio); > > + > No disable for 'level' watchdogs ? Shouldn't it be set to the opposite > of priv->state ? > > > + return 0; > > Since this is an internal function which never returns anything but 0, > you might as well make it void. "level" version will be disabled by "gpio_set_value_cansleep(priv->gpio, !priv->active_low);" line above. "return" is used by "tristate" switch. ... > > +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_before(jiffies, priv->last_jiffies + > > + msecs_to_jiffies(wdd->timeout * 1000))) { > > + /* 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); > > Pretty arbitrary toggle time. Should this be a property ? What about 1/10 of hardware timeout? ... Thanks. ---
On 11/26/2013 11:34 PM, Alexander Shiyan wrote: > Hello. > >> On 11/26/2013 08:26 AM, Alexander Shiyan wrote: >>> This patch adds a watchdog driver for devices controlled through GPIO, >>> (Analog Devices ADM706, IC 555 etc). >>> >>> Signed-off-by: Alexander Shiyan <shc_work@mail.ru> > ... >>> +++ b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt >>> @@ -0,0 +1,23 @@ >>> +* GPIO-controlled Watchdog >>> + >>> +Required Properties: >>> +- compatible: Should contain "linux,wdt-gpio". >> >> Should ? >> >>> +- gpios: From common gpio binding; gpio connection to WDT reset pin. >>> +- wdt-gpio,hw_algo: The algorithm used by the driver. Should be one >>> + of the following values: >> >> Should ? > > What wrong here? > > ... >>> +Example: >>> + watchdog: watchdog { >>> + /* ADM706 */ >>> + compatible = "linux,wdt-gpio"; >> >> Oddly enough, the bindings could be used by non-Linux operating systems, >> but who am I to argue. Fine if this is what the DT maintainers want to see. > > On my opinion this mean that this is not a real hardware, but hardware emulation, > like some other driver does. > > ... >>> diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c >>> new file mode 100644 >>> index 0000000..c7166be >>> --- /dev/null >>> +++ b/drivers/watchdog/gpio_wdt.c >>> @@ -0,0 +1,246 @@ >>> +/* >>> + * 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 int 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) >>> + return gpio_direction_input(priv->gpio); >>> + >> No disable for 'level' watchdogs ? Shouldn't it be set to the opposite >> of priv->state ? >> >>> + return 0; >> >> Since this is an internal function which never returns anything but 0, >> you might as well make it void. > > "level" version will be disabled by > "gpio_set_value_cansleep(priv->gpio, !priv->active_low);" line above. Ok. > "return" is used by "tristate" switch. > Just to return 0. That isn't really necessary. The caller could just return 0 by itself. > ... >>> +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_before(jiffies, priv->last_jiffies + >>> + msecs_to_jiffies(wdd->timeout * 1000))) { >>> + /* 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); >> >> Pretty arbitrary toggle time. Should this be a property ? > > What about 1/10 of hardware timeout? > Even worse, as it is an active wait and not sleep. Not mandatory from my perspective, though; guess the property can be added later if/when needed. 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
diff --git a/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt b/Documentation/devicetree/bindings/watchdog/gpio-wdt.txt new file mode 100644 index 0000000..08ba8e5 --- /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. +- wdt-gpio,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. +- wdt-gpio,hw_margin_ms: Maximum time to reset watchdog circuit (milliseconds). + +Example: + watchdog: watchdog { + /* ADM706 */ + compatible = "linux,wdt-gpio"; + gpios = <&gpio3 9 GPIO_ACTIVE_LOW>; + wdt-gpio,hw_algo = "toggle"; + wdt-gpio,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..c7166be --- /dev/null +++ b/drivers/watchdog/gpio_wdt.c @@ -0,0 +1,246 @@ +/* + * 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 int 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) + return gpio_direction_input(priv->gpio); + + return 0; +} + +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); + + return gpio_wdt_disable(priv); +} + +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 0; +} + +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_before(jiffies, priv->last_jiffies + + msecs_to_jiffies(wdd->timeout * 1000))) { + /* 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; + } + } else + dev_crit(wdd->dev, "Timer expired. System will reboot soon!\n"); +} + +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; + case SYS_DOWN: + 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; + const __be32 *prp; + u32 hw_margin; + 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 = devm_gpio_request_one(&pdev->dev, priv->gpio, GPIOF_IN, + dev_name(&pdev->dev)); + if (ret) + return ret; + + prp = of_get_property(pdev->dev.of_node, "wdt-gpio,hw_algo", NULL); + if (!prp) + return -EINVAL; + if (!strncmp((const char *)prp, "toggle", 6)) + priv->hw_algo = HW_ALGO_TOGGLE; + else if (!strncmp((const char *)prp, "level", 5)) + priv->hw_algo = HW_ALGO_LEVEL; + else + return -ENOTSUPP; + + prp = of_get_property(pdev->dev.of_node, "wdt-gpio,hw_margin_ms", NULL); + if (!prp) + return -EINVAL; + hw_margin = be32_to_cpu(*prp); + /* Disallow values lower than 2 and higher than 65535 ms */ + if ((hw_margin < 2) || (hw_margin > 65535)) + return -EINVAL; + + /* Use safe value (2/3 of real timeout) */ + priv->hw_margin = msecs_to_jiffies(hw_margin * 2 / 3); + + 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); + + priv->notifier.notifier_call = gpio_wdt_notify_sys; + ret = register_reboot_notifier(&priv->notifier); + if (ret) + return ret; + + return watchdog_register_device(&priv->wdd); +} + +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, IC 555 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 | 246 +++++++++++++++++++++ 4 files changed, 278 insertions(+) create mode 100644 Documentation/devicetree/bindings/watchdog/gpio-wdt.txt create mode 100644 drivers/watchdog/gpio_wdt.c