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/*
* Generic Syscon Poweroff Driver
*
* Copyright (c) 2015, National Instruments Corp.
* Author: Moritz Fischer <moritz.fischer@ettus.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kallsyms.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/notifier.h>
#include <linux/mfd/syscon.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/regmap.h>
static struct regmap *map;
static u32 offset;
static u32 mask;
static void syscon_poweroff(void)
{
/* Issue the poweroff */
regmap_write(map, offset, mask);
mdelay(1000);
pr_emerg("Unable to poweroff system\n");
}
static int syscon_poweroff_probe(struct platform_device *pdev)
{
char symname[KSYM_NAME_LEN];
map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
if (IS_ERR(map)) {
dev_err(&pdev->dev, "unable to get syscon");
return PTR_ERR(map);
}
if (of_property_read_u32(pdev->dev.of_node, "offset", &offset)) {
dev_err(&pdev->dev, "unable to read 'offset'");
return -EINVAL;
}
if (of_property_read_u32(pdev->dev.of_node, "mask", &mask)) {
dev_err(&pdev->dev, "unable to read 'mask'");
return -EINVAL;
}
if (pm_power_off) {
lookup_symbol_name((ulong)pm_power_off, symname);
dev_err(&pdev->dev,
"pm_power_off already claimed %p %s",
pm_power_off, symname);
return -EBUSY;
}
pm_power_off = syscon_poweroff;
return 0;
}
static int syscon_poweroff_remove(struct platform_device *pdev)
{
if (pm_power_off == syscon_poweroff)
pm_power_off = NULL;
return 0;
}
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 = syscon_poweroff_remove,
.driver = {
.name = "syscon-poweroff",
.of_match_table = syscon_poweroff_of_match,
},
};
static int __init syscon_poweroff_register(void)
{
return platform_driver_register(&syscon_poweroff_driver);
}
device_initcall(syscon_poweroff_register);
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