/* * Generic Syscon Reboot Driver * * Copyright (c) 2013, Applied Micro Circuits Corporation * Author: Feng Kan <fkan@apm.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #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 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_write(ctx->map, ctx->offset, ctx->mask); 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 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)) return PTR_ERR(ctx->map); if (of_property_read_u32(pdev->dev.of_node, "offset", &ctx->offset)) return -EINVAL; if (of_property_read_u32(pdev->dev.of_node, "mask", &ctx->mask)) return -EINVAL; ctx->restart_handler.notifier_call = syscon_restart_handle; ctx->restart_handler.priority = 192; 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);