1 // SPDX-License-Identifier: GPL-2.0-only
3  * Toggles a GPIO pin to restart a device
7  * Based on the gpio-poweroff driver.
14 #include <linux/gpio/consumer.h>
32 	/* drive it active, also inactive->active edge */  in gpio_restart_notify()
33 	gpiod_direction_output(gpio_restart->reset_gpio, 1);  in gpio_restart_notify()
34 	mdelay(gpio_restart->active_delay_ms);  in gpio_restart_notify()
36 	/* drive inactive, also active->inactive edge */  in gpio_restart_notify()
37 	gpiod_set_value(gpio_restart->reset_gpio, 0);  in gpio_restart_notify()
38 	mdelay(gpio_restart->inactive_delay_ms);  in gpio_restart_notify()
40 	/* drive it active, also inactive->active edge */  in gpio_restart_notify()
41 	gpiod_set_value(gpio_restart->reset_gpio, 1);  in gpio_restart_notify()
44 	mdelay(gpio_restart->wait_delay_ms);  in gpio_restart_notify()
58 	gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart),  in gpio_restart_probe()
61 		return -ENOMEM;  in gpio_restart_probe()
63 	open_source = of_property_read_bool(pdev->dev.of_node, "open-source");  in gpio_restart_probe()
65 	gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL,  in gpio_restart_probe()
67 	ret = PTR_ERR_OR_ZERO(gpio_restart->reset_gpio);  in gpio_restart_probe()
69 		if (ret != -EPROBE_DEFER)  in gpio_restart_probe()
70 			dev_err(&pdev->dev, "Could not get reset GPIO\n");  in gpio_restart_probe()
74 	gpio_restart->restart_handler.notifier_call = gpio_restart_notify;  in gpio_restart_probe()
75 	gpio_restart->restart_handler.priority = 129;  in gpio_restart_probe()
76 	gpio_restart->active_delay_ms = 100;  in gpio_restart_probe()
77 	gpio_restart->inactive_delay_ms = 100;  in gpio_restart_probe()
78 	gpio_restart->wait_delay_ms = 3000;  in gpio_restart_probe()
80 	ret = of_property_read_u32(pdev->dev.of_node, "priority", &property);  in gpio_restart_probe()
83 			dev_err(&pdev->dev, "Invalid priority property: %u\n",  in gpio_restart_probe()
86 			gpio_restart->restart_handler.priority = property;  in gpio_restart_probe()
89 	of_property_read_u32(pdev->dev.of_node, "active-delay",  in gpio_restart_probe()
90 			&gpio_restart->active_delay_ms);  in gpio_restart_probe()
91 	of_property_read_u32(pdev->dev.of_node, "inactive-delay",  in gpio_restart_probe()
92 			&gpio_restart->inactive_delay_ms);  in gpio_restart_probe()
93 	of_property_read_u32(pdev->dev.of_node, "wait-delay",  in gpio_restart_probe()
94 			&gpio_restart->wait_delay_ms);  in gpio_restart_probe()
98 	ret = register_restart_handler(&gpio_restart->restart_handler);  in gpio_restart_probe()
100 		dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n",  in gpio_restart_probe()
102 		return -ENODEV;  in gpio_restart_probe()
113 	ret = unregister_restart_handler(&gpio_restart->restart_handler);  in gpio_restart_remove()
115 		dev_err(&pdev->dev,  in gpio_restart_remove()
116 				"%s: cannot unregister restart handler, %d\n",  in gpio_restart_remove()
122 	{ .compatible = "gpio-restart", },
130 		.name = "restart-gpio",
138 MODULE_DESCRIPTION("GPIO restart driver");