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![Mans Rullgard](/assets/img/avatar_default.png)
Add support for the nowayout option in the gpio watchdog driver. Signed-off-by: Mans Rullgard <mans@mansr.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
196 lines
4.4 KiB
C
196 lines
4.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Driver for watchdog device controlled through GPIO-line
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*
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* Author: 2013, Alexander Shiyan <shc_work@mail.ru>
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*/
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/gpio/consumer.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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#define SOFT_TIMEOUT_MIN 1
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#define SOFT_TIMEOUT_DEF 60
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enum {
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HW_ALGO_TOGGLE,
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HW_ALGO_LEVEL,
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};
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struct gpio_wdt_priv {
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struct gpio_desc *gpiod;
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bool state;
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bool always_running;
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unsigned int hw_algo;
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struct watchdog_device wdd;
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};
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static void gpio_wdt_disable(struct gpio_wdt_priv *priv)
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{
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/* Eternal ping */
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gpiod_set_value_cansleep(priv->gpiod, 1);
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/* Put GPIO back to tristate */
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if (priv->hw_algo == HW_ALGO_TOGGLE)
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gpiod_direction_input(priv->gpiod);
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}
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static int gpio_wdt_ping(struct watchdog_device *wdd)
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{
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struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
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switch (priv->hw_algo) {
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case HW_ALGO_TOGGLE:
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/* Toggle output pin */
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priv->state = !priv->state;
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gpiod_set_value_cansleep(priv->gpiod, priv->state);
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break;
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case HW_ALGO_LEVEL:
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/* Pulse */
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gpiod_set_value_cansleep(priv->gpiod, 1);
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udelay(1);
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gpiod_set_value_cansleep(priv->gpiod, 0);
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break;
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}
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return 0;
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}
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static int gpio_wdt_start(struct watchdog_device *wdd)
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{
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struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
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priv->state = 0;
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gpiod_direction_output(priv->gpiod, priv->state);
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set_bit(WDOG_HW_RUNNING, &wdd->status);
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return gpio_wdt_ping(wdd);
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}
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static int gpio_wdt_stop(struct watchdog_device *wdd)
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{
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struct gpio_wdt_priv *priv = watchdog_get_drvdata(wdd);
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if (!priv->always_running) {
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gpio_wdt_disable(priv);
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} else {
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set_bit(WDOG_HW_RUNNING, &wdd->status);
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}
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return 0;
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}
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static const struct watchdog_info gpio_wdt_ident = {
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.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
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WDIOF_SETTIMEOUT,
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.identity = "GPIO Watchdog",
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};
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static const struct watchdog_ops gpio_wdt_ops = {
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.owner = THIS_MODULE,
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.start = gpio_wdt_start,
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.stop = gpio_wdt_stop,
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.ping = gpio_wdt_ping,
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};
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static int gpio_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct gpio_wdt_priv *priv;
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enum gpiod_flags gflags;
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unsigned int hw_margin;
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const char *algo;
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int ret;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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platform_set_drvdata(pdev, priv);
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ret = of_property_read_string(np, "hw_algo", &algo);
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if (ret)
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return ret;
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if (!strcmp(algo, "toggle")) {
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priv->hw_algo = HW_ALGO_TOGGLE;
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gflags = GPIOD_IN;
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} else if (!strcmp(algo, "level")) {
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priv->hw_algo = HW_ALGO_LEVEL;
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gflags = GPIOD_OUT_LOW;
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} else {
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return -EINVAL;
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}
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priv->gpiod = devm_gpiod_get(dev, NULL, gflags);
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if (IS_ERR(priv->gpiod))
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return PTR_ERR(priv->gpiod);
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ret = of_property_read_u32(np,
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"hw_margin_ms", &hw_margin);
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if (ret)
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return ret;
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/* Disallow values lower than 2 and higher than 65535 ms */
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if (hw_margin < 2 || hw_margin > 65535)
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return -EINVAL;
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priv->always_running = of_property_read_bool(np,
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"always-running");
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watchdog_set_drvdata(&priv->wdd, priv);
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priv->wdd.info = &gpio_wdt_ident;
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priv->wdd.ops = &gpio_wdt_ops;
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priv->wdd.min_timeout = SOFT_TIMEOUT_MIN;
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priv->wdd.max_hw_heartbeat_ms = hw_margin;
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priv->wdd.parent = dev;
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priv->wdd.timeout = SOFT_TIMEOUT_DEF;
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watchdog_init_timeout(&priv->wdd, 0, dev);
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watchdog_set_nowayout(&priv->wdd, nowayout);
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watchdog_stop_on_reboot(&priv->wdd);
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if (priv->always_running)
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gpio_wdt_start(&priv->wdd);
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return devm_watchdog_register_device(dev, &priv->wdd);
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}
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static const struct of_device_id gpio_wdt_dt_ids[] = {
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{ .compatible = "linux,wdt-gpio", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, gpio_wdt_dt_ids);
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static struct platform_driver gpio_wdt_driver = {
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.driver = {
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.name = "gpio-wdt",
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.of_match_table = gpio_wdt_dt_ids,
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},
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.probe = gpio_wdt_probe,
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};
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#ifdef CONFIG_GPIO_WATCHDOG_ARCH_INITCALL
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static int __init gpio_wdt_init(void)
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{
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return platform_driver_register(&gpio_wdt_driver);
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}
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arch_initcall(gpio_wdt_init);
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#else
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module_platform_driver(gpio_wdt_driver);
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#endif
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MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
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MODULE_DESCRIPTION("GPIO Watchdog");
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MODULE_LICENSE("GPL");
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