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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 | // 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.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); |