Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Toggles a GPIO pin to power down a device
 *
 * Jamie Lentin <jm@lentin.co.uk>
 * Andrew Lunn <andrew@lunn.ch>
 *
 * Copyright (C) 2012 Jamie Lentin
 */
#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>
 
#define DEFAULT_TIMEOUT_MS 3000
/*
 * Hold configuration here, cannot be more than one instance of the driver
 * since pm_power_off itself is global.
 */
static struct gpio_desc *reset_gpio;
static u32 timeout = DEFAULT_TIMEOUT_MS;
static u32 active_delay = 100;
static u32 inactive_delay = 100;
 
static void gpio_poweroff_do_poweroff(void)
{
<------>BUG_ON(!reset_gpio);
 
<------>/* drive it active, also inactive->active edge */
<------>gpiod_direction_output(reset_gpio, 1);
<------>mdelay(active_delay);
 
<------>/* drive inactive, also active->inactive edge */
<------>gpiod_set_value_cansleep(reset_gpio, 0);
<------>mdelay(inactive_delay);
 
<------>/* drive it active, also inactive->active edge */
<------>gpiod_set_value_cansleep(reset_gpio, 1);
 
<------>/* give it some time */
<------>mdelay(timeout);
 
<------>WARN_ON(1);
}
 
static int gpio_poweroff_probe(struct platform_device *pdev)
{
<------>bool input = false;
<------>enum gpiod_flags flags;
 
<------>/* If a pm_power_off function has already been added, leave it alone */
<------>if (pm_power_off != NULL) {
<------><------>dev_err(&pdev->dev,
<------><------><------>"%s: pm_power_off function already registered\n",
<------><------>       __func__);
<------><------>return -EBUSY;
<------>}
 
<------>input = device_property_read_bool(&pdev->dev, "input");
<------>if (input)
<------><------>flags = GPIOD_IN;
<------>else
<------><------>flags = GPIOD_OUT_LOW;
 
<------>device_property_read_u32(&pdev->dev, "active-delay-ms", &active_delay);
<------>device_property_read_u32(&pdev->dev, "inactive-delay-ms",
<------><------><------><------> &inactive_delay);
<------>device_property_read_u32(&pdev->dev, "timeout-ms", &timeout);
 
<------>reset_gpio = devm_gpiod_get(&pdev->dev, NULL, flags);
<------>if (IS_ERR(reset_gpio))
<------><------>return PTR_ERR(reset_gpio);
 
<------>pm_power_off = &gpio_poweroff_do_poweroff;
<------>return 0;
}
 
static int gpio_poweroff_remove(struct platform_device *pdev)
{
<------>if (pm_power_off == &gpio_poweroff_do_poweroff)
<------><------>pm_power_off = NULL;
 
<------>return 0;
}
 
static const struct of_device_id of_gpio_poweroff_match[] = {
<------>{ .compatible = "gpio-poweroff", },
<------>{},
};
MODULE_DEVICE_TABLE(of, of_gpio_poweroff_match);
 
static struct platform_driver gpio_poweroff_driver = {
<------>.probe = gpio_poweroff_probe,
<------>.remove = gpio_poweroff_remove,
<------>.driver = {
<------><------>.name = "poweroff-gpio",
<------><------>.of_match_table = of_gpio_poweroff_match,
<------>},
};
 
module_platform_driver(gpio_poweroff_driver);
 
MODULE_AUTHOR("Jamie Lentin <jm@lentin.co.uk>");
MODULE_DESCRIPTION("GPIO poweroff driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:poweroff-gpio");