drivers/thermal/thermal_hwmon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  thermal_hwmon.c - Generic Thermal Management hwmon support.
   4  *
   5  *  Code based on Intel thermal_core.c. Copyrights of the original code:
   6  *  Copyright (C) 2008 Intel Corp
   7  *  Copyright (C) 2008 Zhang Rui <[email protected]>
   8  *  Copyright (C) 2008 Sujith Thomas <[email protected]>
   9  *
  10  *  Copyright (C) 2013 Texas Instruments
  11  *  Copyright (C) 2013 Eduardo Valentin <[email protected]>
  12  */
  13 #include <linux/err.h>
  14 #include <linux/export.h>
  15 #include <linux/hwmon.h>
  16 #include <linux/slab.h>
  17 #include <linux/thermal.h>
  18
  19 #include "thermal_hwmon.h"
  20 #include "thermal_core.h"
  21
  22 /* hwmon sys I/F */
  23 /* thermal zone devices with the same type share one hwmon device */
  24 struct thermal_hwmon_device {
  25         char type[THERMAL_NAME_LENGTH];
  26         struct device *device;
  27         int count;
  28         struct list_head tz_list;
  29         struct list_head node;
  30 };
  31
  32 struct thermal_hwmon_attr {
  33         struct device_attribute attr;
  34         char name[16];
  35 };
  36
  37 /* one temperature input for each thermal zone */
  38 struct thermal_hwmon_temp {
  39         struct list_head hwmon_node;
  40         struct thermal_zone_device *tz;
  41         struct thermal_hwmon_attr temp_input;   /* hwmon sys attr */
  42         struct thermal_hwmon_attr temp_crit;    /* hwmon sys attr */
  43 };
  44
  45 static LIST_HEAD(thermal_hwmon_list);
  46
  47 static DEFINE_MUTEX(thermal_hwmon_list_lock);
  48
  49 static ssize_t
  50 temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
  51 {
  52         int temperature;
  53         int ret;
  54         struct thermal_hwmon_attr *hwmon_attr
  55                         = container_of(attr, struct thermal_hwmon_attr, attr);
  56         struct thermal_hwmon_temp *temp
  57                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  58                                        temp_input);
  59         struct thermal_zone_device *tz = temp->tz;
  60
  61         ret = thermal_zone_get_temp(tz, &temperature);
  62
  63         if (ret)
  64                 return ret;
  65
  66         return sprintf(buf, "%d\n", temperature);
  67 }
  68
  69 static ssize_t
  70 temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
  71 {
  72         struct thermal_hwmon_attr *hwmon_attr
  73                         = container_of(attr, struct thermal_hwmon_attr, attr);
  74         struct thermal_hwmon_temp *temp
  75                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  76                                        temp_crit);
  77         struct thermal_zone_device *tz = temp->tz;
  78         int temperature;
  79         int ret;
  80
  81         mutex_lock(&tz->lock);
  82
  83         if (device_is_registered(&tz->device))
  84                 ret = tz->ops->get_crit_temp(tz, &temperature);
  85         else
  86                 ret = -ENODEV;
  87
  88         mutex_unlock(&tz->lock);
  89
  90         if (ret)
  91                 return ret;
  92
  93         return sprintf(buf, "%d\n", temperature);
  94 }
  95
  96
  97 static struct thermal_hwmon_device *
  98 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
  99 {
 100         struct thermal_hwmon_device *hwmon;
 101         char type[THERMAL_NAME_LENGTH];
 102
 103         mutex_lock(&thermal_hwmon_list_lock);
 104         list_for_each_entry(hwmon, &thermal_hwmon_list, node) {
 105                 strcpy(type, tz->type);
 106                 strreplace(type, '-', '_');
 107                 if (!strcmp(hwmon->type, type)) {
 108                         mutex_unlock(&thermal_hwmon_list_lock);
 109                         return hwmon;
 110                 }
 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         strscpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
 160         strreplace(hwmon->type, '-', '_');
 161         hwmon->device = hwmon_device_register_for_thermal(&tz->device,
 162                                                           hwmon->type, hwmon);
 163         if (IS_ERR(hwmon->device)) {
 164                 result = PTR_ERR(hwmon->device);
 165                 goto free_mem;
 166         }
 167
 168  register_sys_interface:
 169         temp = kzalloc(sizeof(*temp), GFP_KERNEL);
 170         if (!temp) {
 171                 result = -ENOMEM;
 172                 goto unregister_name;
 173         }
 174
 175         temp->tz = tz;
 176         hwmon->count++;
 177
 178         snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
 179                  "temp%d_input", hwmon->count);
 180         temp->temp_input.attr.attr.name = temp->temp_input.name;
 181         temp->temp_input.attr.attr.mode = 0444;
 182         temp->temp_input.attr.show = temp_input_show;
 183         sysfs_attr_init(&temp->temp_input.attr.attr);
 184         result = device_create_file(hwmon->device, &temp->temp_input.attr);
 185         if (result)
 186                 goto free_temp_mem;
 187
 188         if (thermal_zone_crit_temp_valid(tz)) {
 189                 snprintf(temp->temp_crit.name,
 190                                 sizeof(temp->temp_crit.name),
 191                                 "temp%d_crit", hwmon->count);
 192                 temp->temp_crit.attr.attr.name = temp->temp_crit.name;
 193                 temp->temp_crit.attr.attr.mode = 0444;
 194                 temp->temp_crit.attr.show = temp_crit_show;
 195                 sysfs_attr_init(&temp->temp_crit.attr.attr);
 196                 result = device_create_file(hwmon->device,
 197                                             &temp->temp_crit.attr);
 198                 if (result)
 199                         goto unregister_input;
 200         }
 201
 202         mutex_lock(&thermal_hwmon_list_lock);
 203         if (new_hwmon_device)
 204                 list_add_tail(&hwmon->node, &thermal_hwmon_list);
 205         list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
 206         mutex_unlock(&thermal_hwmon_list_lock);
 207
 208         return 0;
 209
 210  unregister_input:
 211         device_remove_file(hwmon->device, &temp->temp_input.attr);
 212  free_temp_mem:
 213         kfree(temp);
 214  unregister_name:
 215         if (new_hwmon_device)
 216                 hwmon_device_unregister(hwmon->device);
 217  free_mem:
 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);
 261
 262 static void devm_thermal_hwmon_release(struct device *dev, void *res)
 263 {
 264         thermal_remove_hwmon_sysfs(*(struct thermal_zone_device **)res);
 265 }
 266
 267 int devm_thermal_add_hwmon_sysfs(struct device *dev, struct thermal_zone_device *tz)
 268 {
 269         struct thermal_zone_device **ptr;
 270         int ret;
 271
 272         ptr = devres_alloc(devm_thermal_hwmon_release, sizeof(*ptr),
 273                            GFP_KERNEL);
 274         if (!ptr) {
 275                 dev_warn(dev, "Failed to allocate device resource data\n");
 276                 return -ENOMEM;
 277         }
 278
 279         ret = thermal_add_hwmon_sysfs(tz);
 280         if (ret) {
 281                 dev_warn(dev, "Failed to add hwmon sysfs attributes\n");
 282                 devres_free(ptr);
 283                 return ret;
 284         }
 285
 286         *ptr = tz;
 287         devres_add(dev, ptr);
 288
 289         return ret;
 290 }
 291 EXPORT_SYMBOL_GPL(devm_thermal_add_hwmon_sysfs);
 292
 293 MODULE_IMPORT_NS(HWMON_THERMAL);