[linux-block.git] / drivers / power / reset / gpio-restart.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Toggles a GPIO pin to restart a device
 *
 * Copyright (C) 2014 Google, Inc.
 *
 * Based on the gpio-poweroff driver.
 */
#include <linux/reboot.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/of_platform.h>
#include <linux/module.h>

struct gpio_restart {
	struct gpio_desc *reset_gpio;
	struct notifier_block restart_handler;
	u32 active_delay_ms;
	u32 inactive_delay_ms;
	u32 wait_delay_ms;
};

static int gpio_restart_notify(struct notifier_block *this,
				unsigned long mode, void *cmd)
{
	struct gpio_restart *gpio_restart =
		container_of(this, struct gpio_restart, restart_handler);

	/* drive it active, also inactive->active edge */
	gpiod_direction_output(gpio_restart->reset_gpio, 1);
	mdelay(gpio_restart->active_delay_ms);

	/* drive inactive, also active->inactive edge */
	gpiod_set_value(gpio_restart->reset_gpio, 0);
	mdelay(gpio_restart->inactive_delay_ms);

	/* drive it active, also inactive->active edge */
	gpiod_set_value(gpio_restart->reset_gpio, 1);

	/* give it some time */
	mdelay(gpio_restart->wait_delay_ms);

	WARN_ON(1);

	return NOTIFY_DONE;
}

static int gpio_restart_probe(struct platform_device *pdev)
{
	struct gpio_restart *gpio_restart;
	bool open_source = false;
	u32 property;
	int ret;

	gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart),
			GFP_KERNEL);
	if (!gpio_restart)
		return -ENOMEM;

	open_source = of_property_read_bool(pdev->dev.of_node, "open-source");

	gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL,
			open_source ? GPIOD_IN : GPIOD_OUT_LOW);
	ret = PTR_ERR_OR_ZERO(gpio_restart->reset_gpio);
	if (ret) {
		if (ret != -EPROBE_DEFER)
			dev_err(&pdev->dev, "Could not get reset GPIO\n");
		return ret;
	}

	gpio_restart->restart_handler.notifier_call = gpio_restart_notify;
	gpio_restart->restart_handler.priority = 129;
	gpio_restart->active_delay_ms = 100;
	gpio_restart->inactive_delay_ms = 100;
	gpio_restart->wait_delay_ms = 3000;

	ret = of_property_read_u32(pdev->dev.of_node, "priority", &property);
	if (!ret) {
		if (property > 255)
			dev_err(&pdev->dev, "Invalid priority property: %u\n",
					property);
		else
			gpio_restart->restart_handler.priority = property;
	}

	of_property_read_u32(pdev->dev.of_node, "active-delay",
			&gpio_restart->active_delay_ms);
	of_property_read_u32(pdev->dev.of_node, "inactive-delay",
			&gpio_restart->inactive_delay_ms);
	of_property_read_u32(pdev->dev.of_node, "wait-delay",
			&gpio_restart->wait_delay_ms);

	platform_set_drvdata(pdev, gpio_restart);

	ret = register_restart_handler(&gpio_restart->restart_handler);
	if (ret) {
		dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n",
				__func__, ret);
		return -ENODEV;
	}

	return 0;
}

static int gpio_restart_remove(struct platform_device *pdev)
{
	struct gpio_restart *gpio_restart = platform_get_drvdata(pdev);
	int ret;

	ret = unregister_restart_handler(&gpio_restart->restart_handler);
	if (ret) {
		dev_err(&pdev->dev,
				"%s: cannot unregister restart handler, %d\n",
				__func__, ret);
		return -ENODEV;
	}

	return 0;
}

static const struct of_device_id of_gpio_restart_match[] = {
	{ .compatible = "gpio-restart", },
	{},
};

static struct platform_driver gpio_restart_driver = {
	.probe = gpio_restart_probe,
	.remove = gpio_restart_remove,
	.driver = {
		.name = "restart-gpio",
		.of_match_table = of_gpio_restart_match,
	},
};

module_platform_driver(gpio_restart_driver);

MODULE_AUTHOR("David Riley <davidriley@chromium.org>");
MODULE_DESCRIPTION("GPIO restart driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
9c92ab61	1	// SPDX-License-Identifier: GPL-2.0-only
371bb20d DR	2	/*
	3	* Toggles a GPIO pin to restart a device
	4	*
	5	* Copyright (C) 2014 Google, Inc.
	6	*
371bb20d DR	7	* Based on the gpio-poweroff driver.
	8	*/
	9	#include <linux/reboot.h>
	10	#include <linux/kernel.h>
	11	#include <linux/init.h>
	12	#include <linux/delay.h>
	13	#include <linux/platform_device.h>
	14	#include <linux/gpio/consumer.h>
	15	#include <linux/of_platform.h>
	16	#include <linux/module.h>
	17
	18	struct gpio_restart {
	19	struct gpio_desc *reset_gpio;
	20	struct notifier_block restart_handler;
	21	u32 active_delay_ms;
	22	u32 inactive_delay_ms;
	23	u32 wait_delay_ms;
	24	};
	25
	26	static int gpio_restart_notify(struct notifier_block *this,
	27	unsigned long mode, void *cmd)
	28	{
	29	struct gpio_restart *gpio_restart =
	30	container_of(this, struct gpio_restart, restart_handler);
	31
	32	/* drive it active, also inactive->active edge */
	33	gpiod_direction_output(gpio_restart->reset_gpio, 1);
	34	mdelay(gpio_restart->active_delay_ms);
	35
	36	/* drive inactive, also active->inactive edge */
	37	gpiod_set_value(gpio_restart->reset_gpio, 0);
	38	mdelay(gpio_restart->inactive_delay_ms);
	39
	40	/* drive it active, also inactive->active edge */
	41	gpiod_set_value(gpio_restart->reset_gpio, 1);
	42
	43	/* give it some time */
	44	mdelay(gpio_restart->wait_delay_ms);
	45
	46	WARN_ON(1);
	47
	48	return NOTIFY_DONE;
	49	}
	50
	51	static int gpio_restart_probe(struct platform_device *pdev)
	52	{
	53	struct gpio_restart *gpio_restart;
	54	bool open_source = false;
	55	u32 property;
	56	int ret;
	57
	58	gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart),
	59	GFP_KERNEL);
	60	if (!gpio_restart)
	61	return -ENOMEM;
	62
	63	open_source = of_property_read_bool(pdev->dev.of_node, "open-source");
	64
	65	gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL,
	66	open_source ? GPIOD_IN : GPIOD_OUT_LOW);
b0d0d3de CP	67	ret = PTR_ERR_OR_ZERO(gpio_restart->reset_gpio);
	68	if (ret) {
	69	if (ret != -EPROBE_DEFER)
	70	dev_err(&pdev->dev, "Could not get reset GPIO\n");
	71	return ret;
371bb20d DR	72	}
	73
	74	gpio_restart->restart_handler.notifier_call = gpio_restart_notify;
bcd56fe1	75	gpio_restart->restart_handler.priority = 129;
371bb20d DR	76	gpio_restart->active_delay_ms = 100;
	77	gpio_restart->inactive_delay_ms = 100;
	78	gpio_restart->wait_delay_ms = 3000;
	79
	80	ret = of_property_read_u32(pdev->dev.of_node, "priority", &property);
	81	if (!ret) {
	82	if (property > 255)
	83	dev_err(&pdev->dev, "Invalid priority property: %u\n",
	84	property);
	85	else
	86	gpio_restart->restart_handler.priority = property;
	87	}
	88
	89	of_property_read_u32(pdev->dev.of_node, "active-delay",
	90	&gpio_restart->active_delay_ms);
	91	of_property_read_u32(pdev->dev.of_node, "inactive-delay",
	92	&gpio_restart->inactive_delay_ms);
	93	of_property_read_u32(pdev->dev.of_node, "wait-delay",
	94	&gpio_restart->wait_delay_ms);
	95
	96	platform_set_drvdata(pdev, gpio_restart);
	97
	98	ret = register_restart_handler(&gpio_restart->restart_handler);
	99	if (ret) {
	100	dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n",
	101	__func__, ret);
	102	return -ENODEV;
	103	}
	104
	105	return 0;
	106	}
	107
	108	static int gpio_restart_remove(struct platform_device *pdev)
	109	{
	110	struct gpio_restart *gpio_restart = platform_get_drvdata(pdev);
	111	int ret;
	112
	113	ret = unregister_restart_handler(&gpio_restart->restart_handler);
	114	if (ret) {
	115	dev_err(&pdev->dev,
	116	"%s: cannot unregister restart handler, %d\n",
	117	__func__, ret);
	118	return -ENODEV;
	119	}
	120
	121	return 0;
	122	}
	123
	124	static const struct of_device_id of_gpio_restart_match[] = {
	125	{ .compatible = "gpio-restart", },
	126	{},
	127	};
	128
	129	static struct platform_driver gpio_restart_driver = {
	130	.probe = gpio_restart_probe,
	131	.remove = gpio_restart_remove,
	132	.driver = {
	133	.name = "restart-gpio",
371bb20d DR	134	.of_match_table = of_gpio_restart_match,
	135	},
	136	};
	137
	138	module_platform_driver(gpio_restart_driver);
	139
	140	MODULE_AUTHOR("David Riley <davidriley@chromium.org>");
	141	MODULE_DESCRIPTION("GPIO restart driver");
	142	MODULE_LICENSE("GPL");