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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Generic Syscon Reboot Driver
*
* Copyright (c) 2013, Applied Micro Circuits Corporation
* Author: Feng Kan <fkan@apm.com>
*/
#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/reboot.h>
#include <linux/regmap.h>
struct syscon_reboot_context {
struct regmap *map;
u32 offset;
u32 value;
u32 mask;
struct notifier_block restart_handler;
};
static int syscon_restart_handle(struct notifier_block *this,
unsigned long mode, void *cmd)
{
struct syscon_reboot_context *ctx =
container_of(this, struct syscon_reboot_context,
restart_handler);
/* Issue the reboot */
regmap_update_bits(ctx->map, ctx->offset, ctx->mask, ctx->value);
mdelay(1000);
pr_emerg("Unable to restart system\n");
return NOTIFY_DONE;
}
static int syscon_reboot_probe(struct platform_device *pdev)
{
struct syscon_reboot_context *ctx;
struct device *dev = &pdev->dev;
int mask_err, value_err;
int priority;
int err;
ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->map = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
if (IS_ERR(ctx->map)) {
ctx->map = syscon_node_to_regmap(dev->parent->of_node);
if (IS_ERR(ctx->map))
return PTR_ERR(ctx->map);
}
if (of_property_read_s32(pdev->dev.of_node, "priority", &priority))
priority = 192;
if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset))
return -EINVAL;
value_err = of_property_read_u32(pdev->dev.of_node, "value", &ctx->value);
mask_err = of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask);
if (value_err && mask_err) {
dev_err(dev, "unable to read 'value' and 'mask'");
return -EINVAL;
}
if (value_err) {
/* support old binding */
ctx->value = ctx->mask;
ctx->mask = 0xFFFFFFFF;
} else if (mask_err) {
/* support value without mask*/
ctx->mask = 0xFFFFFFFF;
}
ctx->restart_handler.notifier_call = syscon_restart_handle;
ctx->restart_handler.priority = priority;
err = register_restart_handler(&ctx->restart_handler);
if (err)
dev_err(dev, "can't register restart notifier (err=%d)\n", err);
return err;
}
static const struct of_device_id syscon_reboot_of_match[] = {
{ .compatible = "syscon-reboot" },
{}
};
static struct platform_driver syscon_reboot_driver = {
.probe = syscon_reboot_probe,
.driver = {
.name = "syscon-reboot",
.of_match_table = syscon_reboot_of_match,
},
};
builtin_platform_driver(syscon_reboot_driver);
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