linux/drivers/watchdog/gpio_wdt.c
Guenter Roeck 03bca15833 watchdog: gpio: Convert to use infrastructure triggered keepalives
The watchdog infrastructure now supports handling watchdog keepalive
if the watchdog is running while the watchdog device is closed.
The infrastructure now also supports generating additional heartbeats
if the maximum hardware timeout is smaller than or close to the
configured timeout. Convert the driver to use this infrastructure.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-06-05 20:39:27 +02:00

210 lines
4.8 KiB
C

/*
* 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/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define SOFT_TIMEOUT_MIN 1
#define SOFT_TIMEOUT_DEF 60
enum {
HW_ALGO_TOGGLE,
HW_ALGO_LEVEL,
};
struct gpio_wdt_priv {
int gpio;
bool active_low;
bool state;
bool always_running;
unsigned int hw_algo;
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_ping(struct watchdog_device *wdd)
{
struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
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;
}
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);
set_bit(WDOG_HW_RUNNING, &wdd->status);
return gpio_wdt_ping(wdd);
}
static int gpio_wdt_stop(struct watchdog_device *wdd)
{
struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
if (!priv->always_running) {
gpio_wdt_disable(priv);
clear_bit(WDOG_HW_RUNNING, &wdd->status);
}
return 0;
}
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,
};
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;
platform_set_drvdata(pdev, priv);
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 (!strcmp(algo, "toggle")) {
priv->hw_algo = HW_ALGO_TOGGLE;
f = GPIOF_IN;
} else if (!strcmp(algo, "level")) {
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;
priv->always_running = of_property_read_bool(pdev->dev.of_node,
"always-running");
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_hw_heartbeat_ms = hw_margin;
priv->wdd.parent = &pdev->dev;
if (watchdog_init_timeout(&priv->wdd, 0, &pdev->dev) < 0)
priv->wdd.timeout = SOFT_TIMEOUT_DEF;
watchdog_stop_on_reboot(&priv->wdd);
if (priv->always_running)
gpio_wdt_start(&priv->wdd);
ret = watchdog_register_device(&priv->wdd);
return ret;
}
static int gpio_wdt_remove(struct platform_device *pdev)
{
struct gpio_wdt_priv *priv = platform_get_drvdata(pdev);
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",
.of_match_table = gpio_wdt_dt_ids,
},
.probe = gpio_wdt_probe,
.remove = gpio_wdt_remove,
};
#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
static int __init gpio_wdt_init(void)
{
return platform_driver_register(&gpio_wdt_driver);
}
arch_initcall(gpio_wdt_init);
#else
module_platform_driver(gpio_wdt_driver);
#endif
MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
MODULE_DESCRIPTION("GPIO Watchdog");
MODULE_LICENSE("GPL");