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100 lines
2.5 KiB
100 lines
2.5 KiB
// 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 <[email protected]> |
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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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