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 temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
  63 {
  64         int temperature;
  65         int ret;
  66         struct thermal_hwmon_attr *hwmon_attr
  67                         = container_of(attr, struct thermal_hwmon_attr, attr);
  68         struct thermal_hwmon_temp *temp
  69                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  70                                        temp_input);
  71         struct thermal_zone_device *tz = temp->tz;
  72
  73         ret = thermal_zone_get_temp(tz, &temperature);
  74
  75         if (ret)
  76                 return ret;
  77
  78         return sprintf(buf, "%d\n", temperature);
  79 }
  80
  81 static ssize_t
  82 temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
  83 {
  84         struct thermal_hwmon_attr *hwmon_attr
  85                         = container_of(attr, struct thermal_hwmon_attr, attr);
  86         struct thermal_hwmon_temp *temp
  87                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  88                                        temp_crit);
  89         struct thermal_zone_device *tz = temp->tz;
  90         int temperature;
  91         int ret;
  92
  93         ret = tz->ops->get_crit_temp(tz, &temperature);
  94         if (ret)
  95                 return ret;
  96
  97         return sprintf(buf, "%d\n", temperature);
  98 }
  99
 100
 101 static struct thermal_hwmon_device *
 102 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
 103 {
 104         struct thermal_hwmon_device *hwmon;
 105
 106         mutex_lock(&thermal_hwmon_list_lock);
 107         list_for_each_entry(hwmon, &thermal_hwmon_list, node)
 108                 if (!strcmp(hwmon->type, tz->type)) {
 109                         mutex_unlock(&thermal_hwmon_list_lock);
 110                         return hwmon;
 111                 }
 112         mutex_unlock(&thermal_hwmon_list_lock);
 113
 114         return NULL;
 115 }
 116
 117 /* Find the temperature input matching a given thermal zone */
 118 static struct thermal_hwmon_temp *
 119 thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
 120                           const struct thermal_zone_device *tz)
 121 {
 122         struct thermal_hwmon_temp *temp;
 123
 124         mutex_lock(&thermal_hwmon_list_lock);
 125         list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
 126                 if (temp->tz == tz) {
 127                         mutex_unlock(&thermal_hwmon_list_lock);
 128                         return temp;
 129                 }
 130         mutex_unlock(&thermal_hwmon_list_lock);
 131
 132         return NULL;
 133 }
 134
 135 static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
 136 {
 137         int temp;
 138         return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
 139 }
 140
 141 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 142 {
 143         struct thermal_hwmon_device *hwmon;
 144         struct thermal_hwmon_temp *temp;
 145         int new_hwmon_device = 1;
 146         int result;
 147
 148         hwmon = thermal_hwmon_lookup_by_type(tz);
 149         if (hwmon) {
 150                 new_hwmon_device = 0;
 151                 goto register_sys_interface;
 152         }
 153
 154         hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
 155         if (!hwmon)
 156                 return -ENOMEM;
 157
 158         INIT_LIST_HEAD(&hwmon->tz_list);
 159         strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
 160         hwmon->device = hwmon_device_register_with_info(NULL, hwmon->type,
 161                                                         hwmon, NULL, NULL);
 162         if (IS_ERR(hwmon->device)) {
 163                 result = PTR_ERR(hwmon->device);
 164                 goto free_mem;
 165         }
 166
 167  register_sys_interface:
 168         temp = kzalloc(sizeof(*temp), GFP_KERNEL);
 169         if (!temp) {
 170                 result = -ENOMEM;
 171                 goto unregister_name;
 172         }
 173
 174         temp->tz = tz;
 175         hwmon->count++;
 176
 177         snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
 178                  "temp%d_input", hwmon->count);
 179         temp->temp_input.attr.attr.name = temp->temp_input.name;
 180         temp->temp_input.attr.attr.mode = 0444;
 181         temp->temp_input.attr.show = temp_input_show;
 182         sysfs_attr_init(&temp->temp_input.attr.attr);
 183         result = device_create_file(hwmon->device, &temp->temp_input.attr);
 184         if (result)
 185                 goto free_temp_mem;
 186
 187         if (thermal_zone_crit_temp_valid(tz)) {
 188                 snprintf(temp->temp_crit.name,
 189                                 sizeof(temp->temp_crit.name),
 190                                 "temp%d_crit", hwmon->count);
 191                 temp->temp_crit.attr.attr.name = temp->temp_crit.name;
 192                 temp->temp_crit.attr.attr.mode = 0444;
 193                 temp->temp_crit.attr.show = temp_crit_show;
 194                 sysfs_attr_init(&temp->temp_crit.attr.attr);
 195                 result = device_create_file(hwmon->device,
 196                                             &temp->temp_crit.attr);
 197                 if (result)
 198                         goto unregister_input;
 199         }
 200
 201         mutex_lock(&thermal_hwmon_list_lock);
 202         if (new_hwmon_device)
 203                 list_add_tail(&hwmon->node, &thermal_hwmon_list);
 204         list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
 205         mutex_unlock(&thermal_hwmon_list_lock);
 206
 207         return 0;
 208
 209  unregister_input:
 210         device_remove_file(hwmon->device, &temp->temp_input.attr);
 211  free_temp_mem:
 212         kfree(temp);
 213  unregister_name:
 214         if (new_hwmon_device)
 215                 hwmon_device_unregister(hwmon->device);
 216  free_mem:
 217         if (new_hwmon_device)
 218                 kfree(hwmon);
 219
 220         return result;
 221 }
 222 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 223
 224 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 225 {
 226         struct thermal_hwmon_device *hwmon;
 227         struct thermal_hwmon_temp *temp;
 228
 229         hwmon = thermal_hwmon_lookup_by_type(tz);
 230         if (unlikely(!hwmon)) {
 231                 /* Should never happen... */
 232                 dev_dbg(&tz->device, "hwmon device lookup failed!\n");
 233                 return;
 234         }
 235
 236         temp = thermal_hwmon_lookup_temp(hwmon, tz);
 237         if (unlikely(!temp)) {
 238                 /* Should never happen... */
 239                 dev_dbg(&tz->device, "temperature input lookup failed!\n");
 240                 return;
 241         }
 242
 243         device_remove_file(hwmon->device, &temp->temp_input.attr);
 244         if (thermal_zone_crit_temp_valid(tz))
 245                 device_remove_file(hwmon->device, &temp->temp_crit.attr);
 246
 247         mutex_lock(&thermal_hwmon_list_lock);
 248         list_del(&temp->hwmon_node);
 249         kfree(temp);
 250         if (!list_empty(&hwmon->tz_list)) {
 251                 mutex_unlock(&thermal_hwmon_list_lock);
 252                 return;
 253         }
 254         list_del(&hwmon->node);
 255         mutex_unlock(&thermal_hwmon_list_lock);
 256
 257         hwmon_device_unregister(hwmon->device);
 258         kfree(hwmon);
 259 }
 260 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);