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142 lines
3.6 KiB
142 lines
3.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Toggles a GPIO pin to restart a device |
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* |
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* Copyright (C) 2014 Google, Inc. |
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* |
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* Based on the gpio-poweroff driver. |
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*/ |
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#include <linux/reboot.h> |
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#include <linux/kernel.h> |
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#include <linux/init.h> |
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#include <linux/delay.h> |
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#include <linux/platform_device.h> |
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#include <linux/gpio/consumer.h> |
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#include <linux/of_platform.h> |
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#include <linux/module.h> |
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struct gpio_restart { |
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struct gpio_desc *reset_gpio; |
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struct notifier_block restart_handler; |
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u32 active_delay_ms; |
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u32 inactive_delay_ms; |
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u32 wait_delay_ms; |
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}; |
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static int gpio_restart_notify(struct notifier_block *this, |
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unsigned long mode, void *cmd) |
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{ |
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struct gpio_restart *gpio_restart = |
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container_of(this, struct gpio_restart, restart_handler); |
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/* drive it active, also inactive->active edge */ |
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gpiod_direction_output(gpio_restart->reset_gpio, 1); |
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mdelay(gpio_restart->active_delay_ms); |
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/* drive inactive, also active->inactive edge */ |
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gpiod_set_value(gpio_restart->reset_gpio, 0); |
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mdelay(gpio_restart->inactive_delay_ms); |
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/* drive it active, also inactive->active edge */ |
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gpiod_set_value(gpio_restart->reset_gpio, 1); |
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/* give it some time */ |
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mdelay(gpio_restart->wait_delay_ms); |
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WARN_ON(1); |
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return NOTIFY_DONE; |
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} |
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static int gpio_restart_probe(struct platform_device *pdev) |
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{ |
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struct gpio_restart *gpio_restart; |
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bool open_source = false; |
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u32 property; |
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int ret; |
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gpio_restart = devm_kzalloc(&pdev->dev, sizeof(*gpio_restart), |
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GFP_KERNEL); |
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if (!gpio_restart) |
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return -ENOMEM; |
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open_source = of_property_read_bool(pdev->dev.of_node, "open-source"); |
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gpio_restart->reset_gpio = devm_gpiod_get(&pdev->dev, NULL, |
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open_source ? GPIOD_IN : GPIOD_OUT_LOW); |
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ret = PTR_ERR_OR_ZERO(gpio_restart->reset_gpio); |
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if (ret) { |
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if (ret != -EPROBE_DEFER) |
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dev_err(&pdev->dev, "Could not get reset GPIO\n"); |
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return ret; |
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} |
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gpio_restart->restart_handler.notifier_call = gpio_restart_notify; |
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gpio_restart->restart_handler.priority = 129; |
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gpio_restart->active_delay_ms = 100; |
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gpio_restart->inactive_delay_ms = 100; |
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gpio_restart->wait_delay_ms = 3000; |
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ret = of_property_read_u32(pdev->dev.of_node, "priority", &property); |
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if (!ret) { |
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if (property > 255) |
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dev_err(&pdev->dev, "Invalid priority property: %u\n", |
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property); |
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else |
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gpio_restart->restart_handler.priority = property; |
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} |
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of_property_read_u32(pdev->dev.of_node, "active-delay", |
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&gpio_restart->active_delay_ms); |
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of_property_read_u32(pdev->dev.of_node, "inactive-delay", |
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&gpio_restart->inactive_delay_ms); |
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of_property_read_u32(pdev->dev.of_node, "wait-delay", |
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&gpio_restart->wait_delay_ms); |
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platform_set_drvdata(pdev, gpio_restart); |
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ret = register_restart_handler(&gpio_restart->restart_handler); |
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if (ret) { |
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dev_err(&pdev->dev, "%s: cannot register restart handler, %d\n", |
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__func__, ret); |
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return -ENODEV; |
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} |
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return 0; |
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} |
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static int gpio_restart_remove(struct platform_device *pdev) |
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{ |
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struct gpio_restart *gpio_restart = platform_get_drvdata(pdev); |
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int ret; |
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ret = unregister_restart_handler(&gpio_restart->restart_handler); |
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if (ret) { |
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dev_err(&pdev->dev, |
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"%s: cannot unregister restart handler, %d\n", |
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__func__, ret); |
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return -ENODEV; |
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} |
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return 0; |
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} |
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static const struct of_device_id of_gpio_restart_match[] = { |
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{ .compatible = "gpio-restart", }, |
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{}, |
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}; |
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static struct platform_driver gpio_restart_driver = { |
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.probe = gpio_restart_probe, |
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.remove = gpio_restart_remove, |
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.driver = { |
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.name = "restart-gpio", |
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.of_match_table = of_gpio_restart_match, |
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}, |
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}; |
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module_platform_driver(gpio_restart_driver); |
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MODULE_AUTHOR("David Riley <[email protected]>"); |
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MODULE_DESCRIPTION("GPIO restart driver"); |
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MODULE_LICENSE("GPL");
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