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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Generic Syscon Poweroff Driver
*
* Copyright (c) 2015, National Instruments Corp.
* Author: Moritz Fischer <moritz.fischer@ettus.com>
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/notifier.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/regmap.h>
static struct regmap *map;
static u32 offset;
static u32 value;
static u32 mask;
static void syscon_poweroff(void)
{
/* Issue the poweroff */
regmap_update_bits(map, offset, mask, value);
mdelay(1000);
pr_emerg("Unable to poweroff system\n");
}
static int syscon_poweroff_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
int mask_err, value_err;
map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
if (IS_ERR(map)) {
map = syscon_node_to_regmap(dev->parent->of_node);
if (IS_ERR(map)) {
dev_err(dev, "unable to get syscon");
return PTR_ERR(map);
}
}
if (of_property_read_u32(dev->of_node, "offset", &offset)) {
dev_err(dev, "unable to read 'offset'");
return -EINVAL;
}
value_err = of_property_read_u32(dev->of_node, "value", &value);
mask_err = of_property_read_u32(dev->of_node, "mask", &mask);
if (value_err && mask_err) {
dev_err(dev, "unable to read 'value' and 'mask'");
return -EINVAL;
}
if (value_err) {
/* support old binding */
value = mask;
mask = 0xFFFFFFFF;
} else if (mask_err) {
/* support value without mask*/
mask = 0xFFFFFFFF;
}
if (pm_power_off) {
dev_err(dev, "pm_power_off already claimed for %ps",
pm_power_off);
return -EBUSY;
}
pm_power_off = syscon_poweroff;
return 0;
}
static void syscon_poweroff_remove(struct platform_device *pdev)
{
if (pm_power_off == syscon_poweroff)
pm_power_off = NULL;
}
static const struct of_device_id syscon_poweroff_of_match[] = {
{ .compatible = "syscon-poweroff" },
{}
};
static struct platform_driver syscon_poweroff_driver = {
.probe = syscon_poweroff_probe,
.remove_new = syscon_poweroff_remove,
.driver = {
.name = "syscon-poweroff",
.of_match_table = syscon_poweroff_of_match,
},
};
builtin_platform_driver(syscon_poweroff_driver);
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