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// 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 <common.h>
#include <driver.h>
#include <poweroff.h>
#include <gpiod.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 int reset_gpio;
static u32 timeout = DEFAULT_TIMEOUT_MS;
static u32 active_delay = 100;
static u32 inactive_delay = 100;
static void gpio_poweroff_do_poweroff(struct poweroff_handler *handler)
{
/* drive it active, also inactive->active edge */
gpio_direction_active(reset_gpio, true);
mdelay(active_delay);
/* drive inactive, also active->inactive edge */
gpio_set_active(reset_gpio, false);
mdelay(inactive_delay);
/* drive it active, also inactive->active edge */
gpio_set_active(reset_gpio, true);
/* give it some time */
mdelay(timeout);
WARN_ON(1);
}
static struct poweroff_handler handler;
static int gpio_poweroff_probe(struct device_d *dev)
{
struct device_node *np = dev->device_node;
bool input = false;
enum gpiod_flags flags;
if (handler.poweroff != NULL) {
dev_err(dev, "%s: pm_power_off function already registered\n", __func__);
return -EBUSY;
}
input = of_property_read_bool(np, "input");
if (input)
flags = GPIOD_IN;
else
flags = GPIOD_OUT_LOW;
of_property_read_u32(np, "active-delay-ms", &active_delay);
of_property_read_u32(np, "inactive-delay-ms", &inactive_delay);
of_property_read_u32(np, "timeout-ms", &timeout);
reset_gpio = gpiod_get(dev, NULL, flags);
if (reset_gpio < 0)
return reset_gpio;
handler.name = "gpio-poweroff";
handler.poweroff = gpio_poweroff_do_poweroff;
handler.priority = 129;
return poweroff_handler_register(&handler);
}
static const struct of_device_id of_gpio_poweroff_match[] = {
{ .compatible = "gpio-poweroff", },
{},
};
static struct driver_d gpio_poweroff_driver = {
.name = "poweroff-gpio",
.of_compatible = of_gpio_poweroff_match,
.probe = gpio_poweroff_probe,
};
device_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");
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