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 <rui.zhang@intel.com>
   8  *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
   9  *
  10  *  Copyright (C) 2013 Texas Instruments
  11  *  Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
  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
  21 /* hwmon sys I/F */
  22 /* thermal zone devices with the same type share one hwmon device */
  23 struct thermal_hwmon_device {
  24         char type[THERMAL_NAME_LENGTH];
  25         struct device *device;
  26         int count;
  27         struct list_head tz_list;
  28         struct list_head node;
  29 };
  30
  31 struct thermal_hwmon_attr {
  32         struct device_attribute attr;
  33         char name[16];
  34 };
  35
  36 /* one temperature input for each thermal zone */
  37 struct thermal_hwmon_temp {
  38         struct list_head hwmon_node;
  39         struct thermal_zone_device *tz;
  40         struct thermal_hwmon_attr temp_input;   /* hwmon sys attr */
  41         struct thermal_hwmon_attr temp_crit;    /* hwmon sys attr */
  42 };
  43
  44 static LIST_HEAD(thermal_hwmon_list);
  45
  46 static DEFINE_MUTEX(thermal_hwmon_list_lock);
  47
  48 static ssize_t
  49 temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
  50 {
  51         int temperature;
  52         int ret;
  53         struct thermal_hwmon_attr *hwmon_attr
  54                         = container_of(attr, struct thermal_hwmon_attr, attr);
  55         struct thermal_hwmon_temp *temp
  56                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  57                                        temp_input);
  58         struct thermal_zone_device *tz = temp->tz;
  59
  60         ret = thermal_zone_get_temp(tz, &temperature);
  61
  62         if (ret)
  63                 return ret;
  64
  65         return sprintf(buf, "%d\n", temperature);
  66 }
  67
  68 static ssize_t
  69 temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
  70 {
  71         struct thermal_hwmon_attr *hwmon_attr
  72                         = container_of(attr, struct thermal_hwmon_attr, attr);
  73         struct thermal_hwmon_temp *temp
  74                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  75                                        temp_crit);
  76         struct thermal_zone_device *tz = temp->tz;
  77         int temperature;
  78         int ret;
  79
  80         mutex_lock(&tz->lock);
  81
  82         if (device_is_registered(&tz->device))
  83                 ret = tz->ops->get_crit_temp(tz, &temperature);
  84         else
  85                 ret = -ENODEV;
  86
  87         mutex_unlock(&tz->lock);
  88
  89         if (ret)
  90                 return ret;
  91
  92         return sprintf(buf, "%d\n", temperature);
  93 }
  94
  95
  96 static struct thermal_hwmon_device *
  97 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
  98 {
  99         struct thermal_hwmon_device *hwmon;
 100         char type[THERMAL_NAME_LENGTH];
 101
 102         mutex_lock(&thermal_hwmon_list_lock);
 103         list_for_each_entry(hwmon, &thermal_hwmon_list, node) {
 104                 strcpy(type, tz->type);
 105                 strreplace(type, '-', '_');
 106                 if (!strcmp(hwmon->type, type)) {
 107                         mutex_unlock(&thermal_hwmon_list_lock);
 108                         return hwmon;
 109                 }
 110         }
 111         mutex_unlock(&thermal_hwmon_list_lock);
 112
 113         return NULL;
 114 }
 115
 116 /* Find the temperature input matching a given thermal zone */
 117 static struct thermal_hwmon_temp *
 118 thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
 119                           const struct thermal_zone_device *tz)
 120 {
 121         struct thermal_hwmon_temp *temp;
 122
 123         mutex_lock(&thermal_hwmon_list_lock);
 124         list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
 125                 if (temp->tz == tz) {
 126                         mutex_unlock(&thermal_hwmon_list_lock);
 127                         return temp;
 128                 }
 129         mutex_unlock(&thermal_hwmon_list_lock);
 130
 131         return NULL;
 132 }
 133
 134 static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
 135 {
 136         int temp;
 137         return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
 138 }
 139
 140 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 141 {
 142         struct thermal_hwmon_device *hwmon;
 143         struct thermal_hwmon_temp *temp;
 144         int new_hwmon_device = 1;
 145         int result;
 146
 147         hwmon = thermal_hwmon_lookup_by_type(tz);
 148         if (hwmon) {
 149                 new_hwmon_device = 0;
 150                 goto register_sys_interface;
 151         }
 152
 153         hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
 154         if (!hwmon)
 155                 return -ENOMEM;
 156
 157         INIT_LIST_HEAD(&hwmon->tz_list);
 158         strscpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
 159         strreplace(hwmon->type, '-', '_');
 160         hwmon->device = hwmon_device_register_for_thermal(&tz->device,
 161                                                           hwmon->type, hwmon);
 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         kfree(hwmon);
 218
 219         return result;
 220 }
 221 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 222
 223 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 224 {
 225         struct thermal_hwmon_device *hwmon;
 226         struct thermal_hwmon_temp *temp;
 227
 228         hwmon = thermal_hwmon_lookup_by_type(tz);
 229         if (unlikely(!hwmon)) {
 230                 /* Should never happen... */
 231                 dev_dbg(&tz->device, "hwmon device lookup failed!\n");
 232                 return;
 233         }
 234
 235         temp = thermal_hwmon_lookup_temp(hwmon, tz);
 236         if (unlikely(!temp)) {
 237                 /* Should never happen... */
 238                 dev_dbg(&tz->device, "temperature input lookup failed!\n");
 239                 return;
 240         }
 241
 242         device_remove_file(hwmon->device, &temp->temp_input.attr);
 243         if (thermal_zone_crit_temp_valid(tz))
 244                 device_remove_file(hwmon->device, &temp->temp_crit.attr);
 245
 246         mutex_lock(&thermal_hwmon_list_lock);
 247         list_del(&temp->hwmon_node);
 248         kfree(temp);
 249         if (!list_empty(&hwmon->tz_list)) {
 250                 mutex_unlock(&thermal_hwmon_list_lock);
 251                 return;
 252         }
 253         list_del(&hwmon->node);
 254         mutex_unlock(&thermal_hwmon_list_lock);
 255
 256         hwmon_device_unregister(hwmon->device);
 257         kfree(hwmon);
 258 }
 259 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);
 260
 261 static void devm_thermal_hwmon_release(struct device *dev, void *res)
 262 {
 263         thermal_remove_hwmon_sysfs(*(struct thermal_zone_device **)res);
 264 }
 265
 266 int devm_thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 267 {
 268         struct thermal_zone_device **ptr;
 269         int ret;
 270
 271         ptr = devres_alloc(devm_thermal_hwmon_release, sizeof(*ptr),
 272                            GFP_KERNEL);
 273         if (!ptr)
 274                 return -ENOMEM;
 275
 276         ret = thermal_add_hwmon_sysfs(tz);
 277         if (ret) {
 278                 devres_free(ptr);
 279                 return ret;
 280         }
 281
 282         *ptr = tz;
 283         devres_add(&tz->device, ptr);
 284
 285         return ret;
 286 }
 287 EXPORT_SYMBOL_GPL(devm_thermal_add_hwmon_sysfs);
 288
 289 MODULE_IMPORT_NS(HWMON_THERMAL);