drivers/power/reset/restart-poweroff.c

   1 /*
   2  * Power off by restarting and let u-boot keep hold of the machine
   3  * until the user presses a button for example.
   4  *
   5  * Andrew Lunn <andrew@lunn.ch>
   6  *
   7  * Copyright (C) 2012 Andrew Lunn
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/module.h>
  18 #include <asm/system_misc.h>
  19
  20 static void restart_poweroff_do_poweroff(void)
  21 {
  22         arm_pm_restart('h', NULL);
  23 }
  24
  25 static int restart_poweroff_probe(struct platform_device *pdev)
  26 {
  27         /* If a pm_power_off function has already been added, leave it alone */
  28         if (pm_power_off != NULL) {
  29                 dev_err(&pdev->dev,
  30                         "pm_power_off function already registered");
  31                 return -EBUSY;
  32         }
  33
  34         pm_power_off = &restart_poweroff_do_poweroff;
  35         return 0;
  36 }
  37
  38 static int restart_poweroff_remove(struct platform_device *pdev)
  39 {
  40         if (pm_power_off == &restart_poweroff_do_poweroff)
  41                 pm_power_off = NULL;
  42
  43         return 0;
  44 }
  45
  46 static const struct of_device_id of_restart_poweroff_match[] = {
  47         { .compatible = "restart-poweroff", },
  48         {},
  49 };
  50
  51 static struct platform_driver restart_poweroff_driver = {
  52         .probe = restart_poweroff_probe,
  53         .remove = restart_poweroff_remove,
  54         .driver = {
  55                 .name = "poweroff-restart",
  56                 .owner = THIS_MODULE,
  57                 .of_match_table = of_restart_poweroff_match,
  58         },
  59 };
  60 module_platform_driver(restart_poweroff_driver);
  61
  62 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch");
  63 MODULE_DESCRIPTION("restart poweroff driver");
  64 MODULE_LICENSE("GPLv2");
  65 MODULE_ALIAS("platform:poweroff-restart");