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/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 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 void vexpress_restart(enum reboot_mode reboot_mode, const char *cmd)
  47 {
  48         vexpress_reset_do(vexpress_restart_device, "restart");
  49 }
  50
  51 static ssize_t vexpress_reset_active_show(struct device *dev,
  52                 struct device_attribute *attr, char *buf)
  53 {
  54         return sprintf(buf, "%d\n", vexpress_restart_device == dev);
  55 }
  56
  57 static ssize_t vexpress_reset_active_store(struct device *dev,
  58                 struct device_attribute *attr, const char *buf, size_t count)
  59 {
  60         long value;
  61         int err = kstrtol(buf, 0, &value);
  62
  63         if (!err && value)
  64                 vexpress_restart_device = dev;
  65
  66         return err ? err : count;
  67 }
  68
  69 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
  70                 vexpress_reset_active_store);
  71
  72
  73 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
  74
  75 static struct of_device_id vexpress_reset_of_match[] = {
  76         {
  77                 .compatible = "arm,vexpress-reset",
  78                 .data = (void *)FUNC_RESET,
  79         }, {
  80                 .compatible = "arm,vexpress-shutdown",
  81                 .data = (void *)FUNC_SHUTDOWN
  82         }, {
  83                 .compatible = "arm,vexpress-reboot",
  84                 .data = (void *)FUNC_REBOOT
  85         },
  86         {}
  87 };
  88
  89 static int vexpress_reset_probe(struct platform_device *pdev)
  90 {
  91         enum vexpress_reset_func func;
  92         const struct of_device_id *match =
  93                         of_match_device(vexpress_reset_of_match, &pdev->dev);
  94         struct regmap *regmap;
  95
  96         if (match)
  97                 func = (enum vexpress_reset_func)match->data;
  98         else
  99                 func = pdev->id_entry->driver_data;
 100
 101         regmap = devm_regmap_init_vexpress_config(&pdev->dev);
 102         if (IS_ERR(regmap))
 103                 return PTR_ERR(regmap);
 104         dev_set_drvdata(&pdev->dev, regmap);
 105
 106         switch (func) {
 107         case FUNC_SHUTDOWN:
 108                 vexpress_power_off_device = &pdev->dev;
 109                 pm_power_off = vexpress_power_off;
 110                 break;
 111         case FUNC_RESET:
 112                 if (!vexpress_restart_device)
 113                         vexpress_restart_device = &pdev->dev;
 114                 arm_pm_restart = vexpress_restart;
 115                 device_create_file(&pdev->dev, &dev_attr_active);
 116                 break;
 117         case FUNC_REBOOT:
 118                 vexpress_restart_device = &pdev->dev;
 119                 arm_pm_restart = vexpress_restart;
 120                 device_create_file(&pdev->dev, &dev_attr_active);
 121                 break;
 122         };
 123
 124         return 0;
 125 }
 126
 127 static const struct platform_device_id vexpress_reset_id_table[] = {
 128         { .name = "vexpress-reset", .driver_data = FUNC_RESET, },
 129         { .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, },
 130         { .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, },
 131         {}
 132 };
 133
 134 static struct platform_driver vexpress_reset_driver = {
 135         .probe = vexpress_reset_probe,
 136         .driver = {
 137                 .name = "vexpress-reset",
 138                 .of_match_table = vexpress_reset_of_match,
 139         },
 140         .id_table = vexpress_reset_id_table,
 141 };
 142
 143 static int __init vexpress_reset_init(void)
 144 {
 145         return platform_driver_register(&vexpress_reset_driver);
 146 }
 147 device_initcall(vexpress_reset_init);