power/reset/syscon-reboot-mode.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
0004  */
0005
0006 #include <linux/init.h>
0007 #include <linux/module.h>
0008 #include <linux/kernel.h>
0009 #include <linux/of.h>
0010 #include <linux/platform_device.h>
0011 #include <linux/reboot.h>
0012 #include <linux/regmap.h>
0013 #include <linux/mfd/syscon.h>
0014 #include <linux/reboot-mode.h>
0015
0016 struct syscon_reboot_mode {
0017     struct regmap *map;
0018     struct reboot_mode_driver reboot;
0019     u32 offset;
0020     u32 mask;
0021 };
0022
0023 static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot,
0024                     unsigned int magic)
0025 {
0026     struct syscon_reboot_mode *syscon_rbm;
0027     int ret;
0028
0029     syscon_rbm = container_of(reboot, struct syscon_reboot_mode, reboot);
0030
0031     ret = regmap_update_bits(syscon_rbm->map, syscon_rbm->offset,
0032                  syscon_rbm->mask, magic);
0033     if (ret < 0)
0034         dev_err(reboot->dev, "update reboot mode bits failed\n");
0035
0036     return ret;
0037 }
0038
0039 static int syscon_reboot_mode_probe(struct platform_device *pdev)
0040 {
0041     int ret;
0042     struct syscon_reboot_mode *syscon_rbm;
0043
0044     syscon_rbm = devm_kzalloc(&pdev->dev, sizeof(*syscon_rbm), GFP_KERNEL);
0045     if (!syscon_rbm)
0046         return -ENOMEM;
0047
0048     syscon_rbm->reboot.dev = &pdev->dev;
0049     syscon_rbm->reboot.write = syscon_reboot_mode_write;
0050     syscon_rbm->mask = 0xffffffff;
0051
0052     syscon_rbm->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
0053     if (IS_ERR(syscon_rbm->map))
0054         return PTR_ERR(syscon_rbm->map);
0055
0056     if (of_property_read_u32(pdev->dev.of_node, "offset",
0057         &syscon_rbm->offset))
0058         return -EINVAL;
0059
0060     of_property_read_u32(pdev->dev.of_node, "mask", &syscon_rbm->mask);
0061
0062     ret = devm_reboot_mode_register(&pdev->dev, &syscon_rbm->reboot);
0063     if (ret)
0064         dev_err(&pdev->dev, "can't register reboot mode\n");
0065
0066     return ret;
0067 }
0068
0069 static const struct of_device_id syscon_reboot_mode_of_match[] = {
0070     { .compatible = "syscon-reboot-mode" },
0071     {}
0072 };
0073 MODULE_DEVICE_TABLE(of, syscon_reboot_mode_of_match);
0074
0075 static struct platform_driver syscon_reboot_mode_driver = {
0076     .probe = syscon_reboot_mode_probe,
0077     .driver = {
0078         .name = "syscon-reboot-mode",
0079         .of_match_table = syscon_reboot_mode_of_match,
0080     },
0081 };
0082 module_platform_driver(syscon_reboot_mode_driver);
0083
0084 MODULE_AUTHOR("Andy Yan <andy.yan@rock-chips.com");
0085 MODULE_DESCRIPTION("SYSCON reboot mode driver");
0086 MODULE_LICENSE("GPL v2");