kernel/drivers/power/reset/vexpress-poweroff.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2012 ARM Limited
  12  */
  13
  14 #include <linux/delay.h>
  15 #include <linux/notifier.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/reboot.h>
  20 #include <linux/stat.h>
  21 #include <linux/vexpress.h>
  22
  23 static void vexpress_reset_do(struct device *dev, const char *what)
  24 {
  25         int err = -ENOENT;
  26         struct regmap *reg = dev_get_drvdata(dev);
  27
  28         if (reg) {
  29                 err = regmap_write(reg, 0, 0);
  30                 if (!err)
  31                         mdelay(1000);
  32         }
  33
  34         dev_emerg(dev, "Unable to %s (%d)\n", what, err);
  35 }
  36
  37 static struct device *vexpress_power_off_device;
  38
  39 static void vexpress_power_off(void)
  40 {
  41         vexpress_reset_do(vexpress_power_off_device, "power off");
  42 }
  43
  44 static struct device *vexpress_restart_device;
  45
  46 static int vexpress_restart(struct notifier_block *this, unsigned long mode,
  47                              void *cmd)
  48 {
  49         vexpress_reset_do(vexpress_restart_device, "restart");
  50
  51         return NOTIFY_DONE;
  52 }
  53
  54 static struct notifier_block vexpress_restart_nb = {
  55         .notifier_call = vexpress_restart,
  56         .priority = 128,
  57 };
  58
  59 static ssize_t vexpress_reset_active_show(struct device *dev,
  60                 struct device_attribute *attr, char *buf)
  61 {
  62         return sprintf(buf, "%d\n", vexpress_restart_device == dev);
  63 }
  64
  65 static ssize_t vexpress_reset_active_store(struct device *dev,
  66                 struct device_attribute *attr, const char *buf, size_t count)
  67 {
  68         long value;
  69         int err = kstrtol(buf, 0, &value);
  70
  71         if (!err && value)
  72                 vexpress_restart_device = dev;
  73
  74         return err ? err : count;
  75 }
  76
  77 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
  78                 vexpress_reset_active_store);
  79
  80
  81 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
  82
  83 static const struct of_device_id vexpress_reset_of_match[] = {
  84         {
  85                 .compatible = "arm,vexpress-reset",
  86                 .data = (void *)FUNC_RESET,
  87         }, {
  88                 .compatible = "arm,vexpress-shutdown",
  89                 .data = (void *)FUNC_SHUTDOWN
  90         }, {
  91                 .compatible = "arm,vexpress-reboot",
  92                 .data = (void *)FUNC_REBOOT
  93         },
  94         {}
  95 };
  96
  97 static int _vexpress_register_restart_handler(struct device *dev)
  98 {
  99         int err;
 100
 101         vexpress_restart_device = dev;
 102         err = register_restart_handler(&vexpress_restart_nb);
 103         if (err) {
 104                 dev_err(dev, "cannot register restart handler (err=%d)\n", err);
 105                 return err;
 106         }
 107         device_create_file(dev, &dev_attr_active);
 108
 109         return 0;
 110 }
 111
 112 static int vexpress_reset_probe(struct platform_device *pdev)
 113 {
 114         const struct of_device_id *match =
 115                         of_match_device(vexpress_reset_of_match, &pdev->dev);
 116         struct regmap *regmap;
 117         int ret = 0;
 118
 119         if (!match)
 120                 return -EINVAL;
 121
 122         regmap = devm_regmap_init_vexpress_config(&pdev->dev);
 123         if (IS_ERR(regmap))
 124                 return PTR_ERR(regmap);
 125         dev_set_drvdata(&pdev->dev, regmap);
 126
 127         switch ((enum vexpress_reset_func)match->data) {
 128         case FUNC_SHUTDOWN:
 129                 vexpress_power_off_device = &pdev->dev;
 130                 pm_power_off = vexpress_power_off;
 131                 break;
 132         case FUNC_RESET:
 133                 if (!vexpress_restart_device)
 134                         ret = _vexpress_register_restart_handler(&pdev->dev);
 135                 break;
 136         case FUNC_REBOOT:
 137                 ret = _vexpress_register_restart_handler(&pdev->dev);
 138                 break;
 139         };
 140
 141         return ret;
 142 }
 143
 144 static struct platform_driver vexpress_reset_driver = {
 145         .probe = vexpress_reset_probe,
 146         .driver = {
 147                 .name = "vexpress-reset",
 148                 .of_match_table = vexpress_reset_of_match,
 149         },
 150 };
 151
 152 static int __init vexpress_reset_init(void)
 153 {
 154         return platform_driver_register(&vexpress_reset_driver);
 155 }
 156 device_initcall(vexpress_reset_init);