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/jiffies.h>
  15 #include <linux/of.h>
  16 #include <linux/of_device.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/stat.h>
  19 #include <linux/vexpress.h>
  20
  21 #include <asm/system_misc.h>
  22
  23 static void vexpress_reset_do(struct device *dev, const char *what)
  24 {
  25         int err = -ENOENT;
  26         struct vexpress_config_func *func =
  27                         vexpress_config_func_get_by_dev(dev);
  28
  29         if (func) {
  30                 unsigned long timeout;
  31
  32                 err = vexpress_config_write(func, 0, 0);
  33
  34                 timeout = jiffies + HZ;
  35                 while (time_before(jiffies, timeout))
  36                         cpu_relax();
  37         }
  38
  39         dev_emerg(dev, "Unable to %s (%d)\n", what, err);
  40 }
  41
  42 static struct device *vexpress_power_off_device;
  43
  44 static void vexpress_power_off(void)
  45 {
  46         vexpress_reset_do(vexpress_power_off_device, "power off");
  47 }
  48
  49 static struct device *vexpress_restart_device;
  50
  51 static void vexpress_restart(char str, const char *cmd)
  52 {
  53         vexpress_reset_do(vexpress_restart_device, "restart");
  54 }
  55
  56 static ssize_t vexpress_reset_active_show(struct device *dev,
  57                 struct device_attribute *attr, char *buf)
  58 {
  59         return sprintf(buf, "%d\n", vexpress_restart_device == dev);
  60 }
  61
  62 static ssize_t vexpress_reset_active_store(struct device *dev,
  63                 struct device_attribute *attr, const char *buf, size_t count)
  64 {
  65         long value;
  66         int err = kstrtol(buf, 0, &value);
  67
  68         if (!err && value)
  69                 vexpress_restart_device = dev;
  70
  71         return err ? err : count;
  72 }
  73
  74 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
  75                 vexpress_reset_active_store);
  76
  77
  78 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
  79
  80 static struct of_device_id vexpress_reset_of_match[] = {
  81         {
  82                 .compatible = "arm,vexpress-reset",
  83                 .data = (void *)FUNC_RESET,
  84         }, {
  85                 .compatible = "arm,vexpress-shutdown",
  86                 .data = (void *)FUNC_SHUTDOWN
  87         }, {
  88                 .compatible = "arm,vexpress-reboot",
  89                 .data = (void *)FUNC_REBOOT
  90         },
  91         {}
  92 };
  93
  94 static int vexpress_reset_probe(struct platform_device *pdev)
  95 {
  96         enum vexpress_reset_func func;
  97         const struct of_device_id *match =
  98                         of_match_device(vexpress_reset_of_match, &pdev->dev);
  99
 100         if (match)
 101                 func = (enum vexpress_reset_func)match->data;
 102         else
 103                 func = pdev->id_entry->driver_data;
 104
 105         switch (func) {
 106         case FUNC_SHUTDOWN:
 107                 vexpress_power_off_device = &pdev->dev;
 108                 pm_power_off = vexpress_power_off;
 109                 break;
 110         case FUNC_RESET:
 111                 if (!vexpress_restart_device)
 112                         vexpress_restart_device = &pdev->dev;
 113                 arm_pm_restart = vexpress_restart;
 114                 device_create_file(&pdev->dev, &dev_attr_active);
 115                 break;
 116         case FUNC_REBOOT:
 117                 vexpress_restart_device = &pdev->dev;
 118                 arm_pm_restart = vexpress_restart;
 119                 device_create_file(&pdev->dev, &dev_attr_active);
 120                 break;
 121         };
 122
 123         return 0;
 124 }
 125
 126 static const struct platform_device_id vexpress_reset_id_table[] = {
 127         { .name = "vexpress-reset", .driver_data = FUNC_RESET, },
 128         { .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, },
 129         { .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, },
 130         {}
 131 };
 132
 133 static struct platform_driver vexpress_reset_driver = {
 134         .probe = vexpress_reset_probe,
 135         .driver = {
 136                 .name = "vexpress-reset",
 137                 .of_match_table = vexpress_reset_of_match,
 138         },
 139         .id_table = vexpress_reset_id_table,
 140 };
 141
 142 static int __init vexpress_reset_init(void)
 143 {
 144         return platform_driver_register(&vexpress_reset_driver);
 145 }
 146 device_initcall(vexpress_reset_init);