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

   1 /*
   2  * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/of.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/reboot.h>
  16 #include <linux/regmap.h>
  17 #include <linux/mfd/syscon.h>
  18 #include "reboot-mode.h"
  19
  20 struct syscon_reboot_mode {
  21         struct regmap *map;
  22         struct reboot_mode_driver reboot;
  23         u32 offset;
  24         u32 mask;
  25 };
  26
  27 static int syscon_reboot_mode_write(struct reboot_mode_driver *reboot,
  28                                     unsigned int magic)
  29 {
  30         struct syscon_reboot_mode *syscon_rbm;
  31         int ret;
  32
  33         syscon_rbm = container_of(reboot, struct syscon_reboot_mode, reboot);
  34
  35         ret = regmap_update_bits(syscon_rbm->map, syscon_rbm->offset,
  36                                  syscon_rbm->mask, magic);
  37         if (ret < 0)
  38                 dev_err(reboot->dev, "update reboot mode bits failed\n");
  39
  40         return ret;
  41 }
  42
  43 static int syscon_reboot_mode_probe(struct platform_device *pdev)
  44 {
  45         int ret;
  46         struct syscon_reboot_mode *syscon_rbm;
  47
  48         syscon_rbm = devm_kzalloc(&pdev->dev, sizeof(*syscon_rbm), GFP_KERNEL);
  49         if (!syscon_rbm)
  50                 return -ENOMEM;
  51
  52         syscon_rbm->reboot.dev = &pdev->dev;
  53         syscon_rbm->reboot.write = syscon_reboot_mode_write;
  54         syscon_rbm->mask = 0xffffffff;
  55
  56         dev_set_drvdata(&pdev->dev, syscon_rbm);
  57
  58         syscon_rbm->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
  59         if (IS_ERR(syscon_rbm->map))
  60                 return PTR_ERR(syscon_rbm->map);
  61
  62         if (of_property_read_u32(pdev->dev.of_node, "offset",
  63             &syscon_rbm->offset))
  64                 return -EINVAL;
  65
  66         of_property_read_u32(pdev->dev.of_node, "mask", &syscon_rbm->mask);
  67
  68         ret = reboot_mode_register(&syscon_rbm->reboot);
  69         if (ret)
  70                 dev_err(&pdev->dev, "can't register reboot mode\n");
  71
  72         return ret;
  73 }
  74
  75 static int syscon_reboot_mode_remove(struct platform_device *pdev)
  76 {
  77         struct syscon_reboot_mode *syscon_rbm = dev_get_drvdata(&pdev->dev);
  78
  79         return reboot_mode_unregister(&syscon_rbm->reboot);
  80 }
  81
  82 static const struct of_device_id syscon_reboot_mode_of_match[] = {
  83         { .compatible = "syscon-reboot-mode" },
  84         {}
  85 };
  86
  87 static struct platform_driver syscon_reboot_mode_driver = {
  88         .probe = syscon_reboot_mode_probe,
  89         .remove = syscon_reboot_mode_remove,
  90         .driver = {
  91                 .name = "syscon-reboot-mode",
  92                 .of_match_table = syscon_reboot_mode_of_match,
  93         },
  94 };
  95 module_platform_driver(syscon_reboot_mode_driver);
  96
  97 MODULE_AUTHOR("Andy Yan <andy.yan@rock-chips.com");
  98 MODULE_DESCRIPTION("SYSCON reboot mode driver");
  99 MODULE_LICENSE("GPL v2");