reset/tps65086-restart.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2021 Emil Renner Berthing
   4  */
   5
   6 #include <linux/mfd/tps65086.h>
   7 #include <linux/mod_devicetable.h>
   8 #include <linux/module.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/reboot.h>
  11
  12 struct tps65086_restart {
  13         struct notifier_block handler;
  14         struct device *dev;
  15 };
  16
  17 static int tps65086_restart_notify(struct notifier_block *this,
  18                                    unsigned long mode, void *cmd)
  19 {
  20         struct tps65086_restart *tps65086_restart =
  21                 container_of(this, struct tps65086_restart, handler);
  22         struct tps65086 *tps65086 = dev_get_drvdata(tps65086_restart->dev->parent);
  23         int ret;
  24
  25         ret = regmap_write(tps65086->regmap, TPS65086_FORCESHUTDN, 1);
  26         if (ret) {
  27                 dev_err(tps65086_restart->dev, "%s: error writing to tps65086 pmic: %d\n",
  28                         __func__, ret);
  29                 return NOTIFY_DONE;
  30         }
  31
  32         /* give it a little time */
  33         mdelay(200);
  34
  35         WARN_ON(1);
  36
  37         return NOTIFY_DONE;
  38 }
  39
  40 static int tps65086_restart_probe(struct platform_device *pdev)
  41 {
  42         struct tps65086_restart *tps65086_restart;
  43         int ret;
  44
  45         tps65086_restart = devm_kzalloc(&pdev->dev, sizeof(*tps65086_restart), GFP_KERNEL);
  46         if (!tps65086_restart)
  47                 return -ENOMEM;
  48
  49         platform_set_drvdata(pdev, tps65086_restart);
  50
  51         tps65086_restart->handler.notifier_call = tps65086_restart_notify;
  52         tps65086_restart->handler.priority = 192;
  53         tps65086_restart->dev = &pdev->dev;
  54
  55         ret = register_restart_handler(&tps65086_restart->handler);
  56         if (ret) {
  57                 dev_err(&pdev->dev, "%s: cannot register restart handler: %d\n",
  58                         __func__, ret);
  59                 return -ENODEV;
  60         }
  61
  62         return 0;
  63 }
  64
  65 static int tps65086_restart_remove(struct platform_device *pdev)
  66 {
  67         struct tps65086_restart *tps65086_restart = platform_get_drvdata(pdev);
  68         int ret;
  69
  70         ret = unregister_restart_handler(&tps65086_restart->handler);
  71         if (ret) {
  72                 dev_err(&pdev->dev, "%s: cannot unregister restart handler: %d\n",
  73                         __func__, ret);
  74                 return -ENODEV;
  75         }
  76
  77         return 0;
  78 }
  79
  80 static const struct platform_device_id tps65086_restart_id_table[] = {
  81         { "tps65086-reset", },
  82         { /* sentinel */ }
  83 };
  84 MODULE_DEVICE_TABLE(platform, tps65086_restart_id_table);
  85
  86 static struct platform_driver tps65086_restart_driver = {
  87         .driver = {
  88                 .name = "tps65086-restart",
  89         },
  90         .probe = tps65086_restart_probe,
  91         .remove = tps65086_restart_remove,
  92         .id_table = tps65086_restart_id_table,
  93 };
  94 module_platform_driver(tps65086_restart_driver);
  95
  96 MODULE_AUTHOR("Emil Renner Berthing <kernel@esmil.dk>");
  97 MODULE_DESCRIPTION("TPS65086 restart driver");