u-boot/drivers/sysreset/poweroff_gpio.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Toggles a GPIO pin to power down a device
*
* Created using the Linux driver as reference, which
* has been written by:
*
* Jamie Lentin <jm@lentin.co.uk>
* Andrew Lunn <andrew@lunn.ch>
*
* Copyright (C) 2012 Jamie Lentin
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <sysreset.h>
#include <asm/gpio.h>
#include <linux/delay.h>
struct poweroff_gpio_info {
struct gpio_desc gpio;
u32 active_delay_ms;
u32 inactive_delay_ms;
u32 timeout_ms;
};
static int poweroff_gpio_request(struct udevice *dev, enum sysreset_t type)
{
struct poweroff_gpio_info *priv = dev_get_priv(dev);
int r;
if (type != SYSRESET_POWER_OFF)
return -ENOSYS;
debug("GPIO poweroff\n");
/* drive it active, also inactive->active edge */
r = dm_gpio_set_value(&priv->gpio, 1);
if (r < 0)
return r;
mdelay(priv->active_delay_ms);
/* drive inactive, also active->inactive edge */
r = dm_gpio_set_value(&priv->gpio, 0);
if (r < 0)
return r;
mdelay(priv->inactive_delay_ms);
/* drive it active, also inactive->active edge */
r = dm_gpio_set_value(&priv->gpio, 1);
if (r < 0)
return r;
/* give it some time */
mdelay(priv->timeout_ms);
return -EINPROGRESS;
}
static int poweroff_gpio_probe(struct udevice *dev)
{
struct poweroff_gpio_info *priv = dev_get_priv(dev);
int flags;
flags = dev_read_bool(dev, "input") ? GPIOD_IS_IN : GPIOD_IS_OUT;
priv->active_delay_ms = dev_read_u32_default(dev, "active-delay-ms", 100);
priv->inactive_delay_ms = dev_read_u32_default(dev, "inactive-delay-ms", 100);
priv->timeout_ms = dev_read_u32_default(dev, "timeout-ms", 3000);
return gpio_request_by_name(dev, "gpios", 0, &priv->gpio, flags);
}
static struct sysreset_ops poweroff_gpio_ops = {
.request = poweroff_gpio_request,
};
static const struct udevice_id poweroff_gpio_ids[] = {
{ .compatible = "gpio-poweroff", },
{},
};
U_BOOT_DRIVER(poweroff_gpio) = {
.name = "poweroff-gpio",
.id = UCLASS_SYSRESET,
.ops = &poweroff_gpio_ops,
.probe = poweroff_gpio_probe,
.priv_auto = sizeof(struct poweroff_gpio_info),
.of_match = poweroff_gpio_ids,
};