| // 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 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; |
| |
| 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 = 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); |