![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
190 lines
4.2 KiB
C
190 lines
4.2 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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#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_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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