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