drivers/power/reset/syscon-reboot-mode.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/module.h>
   8 #include <linux/kernel.h>
   9 #include <linux/of.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/reboot.h>
  12 #include <linux/regmap.h>
  13 #include <linux/mfd/syscon.h>
  14 #include <linux/reboot-mode.h>
  15
  16 struct syscon_reboot_mode {
  17         struct regmap *map;
  18         struct reboot_mode_driver reboot;
  19         u32 offset;
  20         u32 mask;
  21 };
  22
  23 static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot,
  24                                     unsigned int magic)
  25 {
  26         struct syscon_reboot_mode *syscon_rbm;
  27         int ret;
  28
  29         syscon_rbm = container_of(reboot, struct syscon_reboot_mode, reboot);
  30
  31         ret = regmap_update_bits(syscon_rbm->map, syscon_rbm->offset,
  32                                  syscon_rbm->mask, magic);
  33         if (ret < 0)
  34                 dev_err(reboot->dev, "update reboot mode bits failed\n");
  35
  36         return ret;
  37 }
  38
  39 static int syscon_reboot_mode_probe(struct platform_device *pdev)
  40 {
  41         int ret;
  42         struct syscon_reboot_mode *syscon_rbm;
  43
  44         syscon_rbm = devm_kzalloc(&pdev->dev, sizeof(*syscon_rbm), GFP_KERNEL);
  45         if (!syscon_rbm)
  46                 return -ENOMEM;
  47
  48         syscon_rbm->reboot.dev = &pdev->dev;
  49         syscon_rbm->reboot.write = syscon_reboot_mode_write;
  50         syscon_rbm->mask = 0xffffffff;
  51
  52         syscon_rbm->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
  53         if (IS_ERR(syscon_rbm->map))
  54                 return PTR_ERR(syscon_rbm->map);
  55
  56         if (of_property_read_u32(pdev->dev.of_node, "offset",
  57             &syscon_rbm->offset))
  58                 return -EINVAL;
  59
  60         of_property_read_u32(pdev->dev.of_node, "mask", &syscon_rbm->mask);
  61
  62         ret = devm_reboot_mode_register(&pdev->dev, &syscon_rbm->reboot);
  63         if (ret)
  64                 dev_err(&pdev->dev, "can't register reboot mode\n");
  65
  66         return ret;
  67 }
  68
  69 static const struct of_device_id syscon_reboot_mode_of_match[] = {
  70         { .compatible = "syscon-reboot-mode" },
  71         {}
  72 };
  73 MODULE_DEVICE_TABLE(of, syscon_reboot_mode_of_match);
  74
  75 static struct platform_driver syscon_reboot_mode_driver = {
  76         .probe = syscon_reboot_mode_probe,
  77         .driver = {
  78                 .name = "syscon-reboot-mode",
  79                 .of_match_table = syscon_reboot_mode_of_match,
  80         },
  81 };
  82 module_platform_driver(syscon_reboot_mode_driver);
  83
  84 MODULE_AUTHOR("Andy Yan <andy.yan@rock-chips.com");
  85 MODULE_DESCRIPTION("SYSCON reboot mode driver");
  86 MODULE_LICENSE("GPL v2");