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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2014 STMicroelectronics
*
* Power off Restart driver, used in STMicroelectronics devices.
*
* Author: Christophe Kerello <christophe.kerello@st.com>
*/
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/mfd/syscon.h>
#include <linux/reboot.h>
#include <linux/regmap.h>
struct reset_syscfg {
struct regmap *regmap;
/* syscfg used for reset */
unsigned int offset_rst;
unsigned int mask_rst;
/* syscfg used for unmask the reset */
unsigned int offset_rst_msk;
unsigned int mask_rst_msk;
};
/* STiH407 */
#define STIH407_SYSCFG_4000 0x0
#define STIH407_SYSCFG_4008 0x20
static struct reset_syscfg stih407_reset = {
.offset_rst = STIH407_SYSCFG_4000,
.mask_rst = BIT(0),
.offset_rst_msk = STIH407_SYSCFG_4008,
.mask_rst_msk = BIT(0)
};
static struct reset_syscfg *st_restart_syscfg;
static int st_restart(struct notifier_block *this, unsigned long mode,
void *cmd)
{
/* reset syscfg updated */
regmap_update_bits(st_restart_syscfg->regmap,
st_restart_syscfg->offset_rst,
st_restart_syscfg->mask_rst,
0);
/* unmask the reset */
regmap_update_bits(st_restart_syscfg->regmap,
st_restart_syscfg->offset_rst_msk,
st_restart_syscfg->mask_rst_msk,
0);
return NOTIFY_DONE;
}
static struct notifier_block st_restart_nb = {
.notifier_call = st_restart,
.priority = 192,
};
static const struct of_device_id st_reset_of_match[] = {
{
.compatible = "st,stih407-restart",
.data = (void *)&stih407_reset,
},
{}
};
static int st_reset_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
const struct of_device_id *match;
struct device *dev = &pdev->dev;
match = of_match_device(st_reset_of_match, dev);
if (!match)
return -ENODEV;
st_restart_syscfg = (struct reset_syscfg *)match->data;
st_restart_syscfg->regmap =
syscon_regmap_lookup_by_phandle(np, "st,syscfg");
if (IS_ERR(st_restart_syscfg->regmap)) {
dev_err(dev, "No syscfg phandle specified\n");
return PTR_ERR(st_restart_syscfg->regmap);
}
return register_restart_handler(&st_restart_nb);
}
static struct platform_driver st_reset_driver = {
.probe = st_reset_probe,
.driver = {
.name = "st_reset",
.of_match_table = st_reset_of_match,
},
};
builtin_platform_driver(st_reset_driver);
MODULE_AUTHOR("Christophe Kerello <christophe.kerello@st.com>");
MODULE_DESCRIPTION("STMicroelectronics Power off Restart driver");
MODULE_LICENSE("GPL v2");
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