drivers/thermal/thermal_hwmon.c

   1 /*
   2  *  thermal_hwmon.c - Generic Thermal Management hwmon support.
   3  *
   4  *  Code based on Intel thermal_core.c. Copyrights of the original code:
   5  *  Copyright (C) 2008 Intel Corp
   6  *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
   7  *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
   8  *
   9  *  Copyright (C) 2013 Texas Instruments
  10  *  Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
  11  *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License as published by
  15  *  the Free Software Foundation; version 2 of the License.
  16  *
  17  *  This program is distributed in the hope that it will be useful, but
  18  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  *  General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License along
  23  *  with this program; if not, write to the Free Software Foundation, Inc.,
  24  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  25  *
  26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  27  */
  28 #include <linux/hwmon.h>
  29 #include <linux/thermal.h>
  30 #include <linux/slab.h>
  31 #include <linux/err.h>
  32 #include "thermal_hwmon.h"
  33
  34 /* hwmon sys I/F */
  35 /* thermal zone devices with the same type share one hwmon device */
  36 struct thermal_hwmon_device {
  37         char type[THERMAL_NAME_LENGTH];
  38         struct device *device;
  39         int count;
  40         struct list_head tz_list;
  41         struct list_head node;
  42 };
  43
  44 struct thermal_hwmon_attr {
  45         struct device_attribute attr;
  46         char name[16];
  47 };
  48
  49 /* one temperature input for each thermal zone */
  50 struct thermal_hwmon_temp {
  51         struct list_head hwmon_node;
  52         struct thermal_zone_device *tz;
  53         struct thermal_hwmon_attr temp_input;   /* hwmon sys attr */
  54         struct thermal_hwmon_attr temp_crit;    /* hwmon sys attr */
  55 };
  56
  57 static LIST_HEAD(thermal_hwmon_list);
  58
  59 static DEFINE_MUTEX(thermal_hwmon_list_lock);
  60
  61 static ssize_t
  62 name_show(struct device *dev, struct device_attribute *attr, char *buf)
  63 {
  64         struct thermal_hwmon_device *hwmon = dev_get_drvdata(dev);
  65         return sprintf(buf, "%s\n", hwmon->type);
  66 }
  67 static DEVICE_ATTR(name, 0444, name_show, NULL);
  68
  69 static ssize_t
  70 temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
  71 {
  72         int temperature;
  73         int ret;
  74         struct thermal_hwmon_attr *hwmon_attr
  75                         = container_of(attr, struct thermal_hwmon_attr, attr);
  76         struct thermal_hwmon_temp *temp
  77                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  78                                        temp_input);
  79         struct thermal_zone_device *tz = temp->tz;
  80
  81         ret = thermal_zone_get_temp(tz, &temperature);
  82
  83         if (ret)
  84                 return ret;
  85
  86         return sprintf(buf, "%d\n", temperature);
  87 }
  88
  89 static ssize_t
  90 temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
  91 {
  92         struct thermal_hwmon_attr *hwmon_attr
  93                         = container_of(attr, struct thermal_hwmon_attr, attr);
  94         struct thermal_hwmon_temp *temp
  95                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  96                                        temp_crit);
  97         struct thermal_zone_device *tz = temp->tz;
  98         int temperature;
  99         int ret;
 100
 101         ret = tz->ops->get_trip_temp(tz, 0, &temperature);
 102         if (ret)
 103                 return ret;
 104
 105         return sprintf(buf, "%d\n", temperature);
 106 }
 107
 108
 109 static struct thermal_hwmon_device *
 110 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
 111 {
 112         struct thermal_hwmon_device *hwmon;
 113
 114         mutex_lock(&thermal_hwmon_list_lock);
 115         list_for_each_entry(hwmon, &thermal_hwmon_list, node)
 116                 if (!strcmp(hwmon->type, tz->type)) {
 117                         mutex_unlock(&thermal_hwmon_list_lock);
 118                         return hwmon;
 119                 }
 120         mutex_unlock(&thermal_hwmon_list_lock);
 121
 122         return NULL;
 123 }
 124
 125 /* Find the temperature input matching a given thermal zone */
 126 static struct thermal_hwmon_temp *
 127 thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
 128                           const struct thermal_zone_device *tz)
 129 {
 130         struct thermal_hwmon_temp *temp;
 131
 132         mutex_lock(&thermal_hwmon_list_lock);
 133         list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
 134                 if (temp->tz == tz) {
 135                         mutex_unlock(&thermal_hwmon_list_lock);
 136                         return temp;
 137                 }
 138         mutex_unlock(&thermal_hwmon_list_lock);
 139
 140         return NULL;
 141 }
 142
 143 static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
 144 {
 145         int temp;
 146         return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
 147 }
 148
 149 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 150 {
 151         struct thermal_hwmon_device *hwmon;
 152         struct thermal_hwmon_temp *temp;
 153         int new_hwmon_device = 1;
 154         int result;
 155
 156         hwmon = thermal_hwmon_lookup_by_type(tz);
 157         if (hwmon) {
 158                 new_hwmon_device = 0;
 159                 goto register_sys_interface;
 160         }
 161
 162         hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
 163         if (!hwmon)
 164                 return -ENOMEM;
 165
 166         INIT_LIST_HEAD(&hwmon->tz_list);
 167         strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
 168         hwmon->device = hwmon_device_register(NULL);
 169         if (IS_ERR(hwmon->device)) {
 170                 result = PTR_ERR(hwmon->device);
 171                 goto free_mem;
 172         }
 173         dev_set_drvdata(hwmon->device, hwmon);
 174         result = device_create_file(hwmon->device, &dev_attr_name);
 175         if (result)
 176                 goto free_mem;
 177
 178  register_sys_interface:
 179         temp = kzalloc(sizeof(*temp), GFP_KERNEL);
 180         if (!temp) {
 181                 result = -ENOMEM;
 182                 goto unregister_name;
 183         }
 184
 185         temp->tz = tz;
 186         hwmon->count++;
 187
 188         snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
 189                  "temp%d_input", hwmon->count);
 190         temp->temp_input.attr.attr.name = temp->temp_input.name;
 191         temp->temp_input.attr.attr.mode = 0444;
 192         temp->temp_input.attr.show = temp_input_show;
 193         sysfs_attr_init(&temp->temp_input.attr.attr);
 194         result = device_create_file(hwmon->device, &temp->temp_input.attr);
 195         if (result)
 196                 goto free_temp_mem;
 197
 198         if (thermal_zone_crit_temp_valid(tz)) {
 199                 snprintf(temp->temp_crit.name,
 200                                 sizeof(temp->temp_crit.name),
 201                                 "temp%d_crit", hwmon->count);
 202                 temp->temp_crit.attr.attr.name = temp->temp_crit.name;
 203                 temp->temp_crit.attr.attr.mode = 0444;
 204                 temp->temp_crit.attr.show = temp_crit_show;
 205                 sysfs_attr_init(&temp->temp_crit.attr.attr);
 206                 result = device_create_file(hwmon->device,
 207                                             &temp->temp_crit.attr);
 208                 if (result)
 209                         goto unregister_input;
 210         }
 211
 212         mutex_lock(&thermal_hwmon_list_lock);
 213         if (new_hwmon_device)
 214                 list_add_tail(&hwmon->node, &thermal_hwmon_list);
 215         list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
 216         mutex_unlock(&thermal_hwmon_list_lock);
 217
 218         return 0;
 219
 220  unregister_input:
 221         device_remove_file(hwmon->device, &temp->temp_input.attr);
 222  free_temp_mem:
 223         kfree(temp);
 224  unregister_name:
 225         if (new_hwmon_device) {
 226                 device_remove_file(hwmon->device, &dev_attr_name);
 227                 hwmon_device_unregister(hwmon->device);
 228         }
 229  free_mem:
 230         if (new_hwmon_device)
 231                 kfree(hwmon);
 232
 233         return result;
 234 }
 235 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 236
 237 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 238 {
 239         struct thermal_hwmon_device *hwmon;
 240         struct thermal_hwmon_temp *temp;
 241
 242         hwmon = thermal_hwmon_lookup_by_type(tz);
 243         if (unlikely(!hwmon)) {
 244                 /* Should never happen... */
 245                 dev_dbg(&tz->device, "hwmon device lookup failed!\n");
 246                 return;
 247         }
 248
 249         temp = thermal_hwmon_lookup_temp(hwmon, tz);
 250         if (unlikely(!temp)) {
 251                 /* Should never happen... */
 252                 dev_dbg(&tz->device, "temperature input lookup failed!\n");
 253                 return;
 254         }
 255
 256         device_remove_file(hwmon->device, &temp->temp_input.attr);
 257         if (thermal_zone_crit_temp_valid(tz))
 258                 device_remove_file(hwmon->device, &temp->temp_crit.attr);
 259
 260         mutex_lock(&thermal_hwmon_list_lock);
 261         list_del(&temp->hwmon_node);
 262         kfree(temp);
 263         if (!list_empty(&hwmon->tz_list)) {
 264                 mutex_unlock(&thermal_hwmon_list_lock);
 265                 return;
 266         }
 267         list_del(&hwmon->node);
 268         mutex_unlock(&thermal_hwmon_list_lock);
 269
 270         device_remove_file(hwmon->device, &dev_attr_name);
 271         hwmon_device_unregister(hwmon->device);
 272         kfree(hwmon);
 273 }
 274 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);