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// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2012 ARM Limited
*/
#include <linux/delay.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/stat.h>
#include <linux/vexpress.h>
static void vexpress_reset_do(struct device *dev, const char *what)
{
int err = -ENOENT;
struct regmap *reg = dev_get_drvdata(dev);
if (reg) {
err = regmap_write(reg, 0, 0);
if (!err)
mdelay(1000);
}
dev_emerg(dev, "Unable to %s (%d)\n", what, err);
}
static struct device *vexpress_power_off_device;
static atomic_t vexpress_restart_nb_refcnt = ATOMIC_INIT(0);
static void vexpress_power_off(void)
{
vexpress_reset_do(vexpress_power_off_device, "power off");
}
static struct device *vexpress_restart_device;
static int vexpress_restart(struct notifier_block *this, unsigned long mode,
void *cmd)
{
vexpress_reset_do(vexpress_restart_device, "restart");
return NOTIFY_DONE;
}
static struct notifier_block vexpress_restart_nb = {
.notifier_call = vexpress_restart,
.priority = 128,
};
static ssize_t vexpress_reset_active_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", vexpress_restart_device == dev);
}
static ssize_t vexpress_reset_active_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
long value;
int err = kstrtol(buf, 0, &value);
if (!err && value)
vexpress_restart_device = dev;
return err ? err : count;
}
static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
vexpress_reset_active_store);
enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
static const struct of_device_id vexpress_reset_of_match[] = {
{
.compatible = "arm,vexpress-reset",
.data = (void *)FUNC_RESET,
}, {
.compatible = "arm,vexpress-shutdown",
.data = (void *)FUNC_SHUTDOWN
}, {
.compatible = "arm,vexpress-reboot",
.data = (void *)FUNC_REBOOT
},
{}
};
static int _vexpress_register_restart_handler(struct device *dev)
{
int err;
vexpress_restart_device = dev;
if (atomic_inc_return(&vexpress_restart_nb_refcnt) == 1) {
err = register_restart_handler(&vexpress_restart_nb);
if (err) {
dev_err(dev, "cannot register restart handler (err=%d)\n", err);
atomic_dec(&vexpress_restart_nb_refcnt);
return err;
}
}
device_create_file(dev, &dev_attr_active);
return 0;
}
static int vexpress_reset_probe(struct platform_device *pdev)
{
const struct of_device_id *match =
of_match_device(vexpress_reset_of_match, &pdev->dev);
struct regmap *regmap;
int ret = 0;
if (!match)
return -EINVAL;
regmap = devm_regmap_init_vexpress_config(&pdev->dev);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
dev_set_drvdata(&pdev->dev, regmap);
switch ((uintptr_t)match->data) {
case FUNC_SHUTDOWN:
vexpress_power_off_device = &pdev->dev;
pm_power_off = vexpress_power_off;
break;
case FUNC_RESET:
if (!vexpress_restart_device)
ret = _vexpress_register_restart_handler(&pdev->dev);
break;
case FUNC_REBOOT:
ret = _vexpress_register_restart_handler(&pdev->dev);
break;
}
return ret;
}
static struct platform_driver vexpress_reset_driver = {
.probe = vexpress_reset_probe,
.driver = {
.name = "vexpress-reset",
.of_match_table = vexpress_reset_of_match,
.suppress_bind_attrs = true,
},
};
builtin_platform_driver(vexpress_reset_driver);
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