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         guard(thermal_zone)(tz);
  82
  83         ret = tz->ops.get_crit_temp(tz, &temperature);
  84         if (ret)
  85                 return ret;
  86
  87         return sprintf(buf, "%d\n", temperature);
  88 }
  89
  90
  91 static struct thermal_hwmon_device *
  92 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
  93 {
  94         struct thermal_hwmon_device *hwmon;
  95         char type[THERMAL_NAME_LENGTH];
  96
  97         mutex_lock(&thermal_hwmon_list_lock);
  98         list_for_each_entry(hwmon, &thermal_hwmon_list, node) {
  99                 strcpy(type, tz->type);
 100                 strreplace(type, '-', '_');
 101                 if (!strcmp(hwmon->type, type)) {
 102                         mutex_unlock(&thermal_hwmon_list_lock);
 103                         return hwmon;
 104                 }
 105         }
 106         mutex_unlock(&thermal_hwmon_list_lock);
 107
 108         return NULL;
 109 }
 110
 111 /* Find the temperature input matching a given thermal zone */
 112 static struct thermal_hwmon_temp *
 113 thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
 114                           const struct thermal_zone_device *tz)
 115 {
 116         struct thermal_hwmon_temp *temp;
 117
 118         mutex_lock(&thermal_hwmon_list_lock);
 119         list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
 120                 if (temp->tz == tz) {
 121                         mutex_unlock(&thermal_hwmon_list_lock);
 122                         return temp;
 123                 }
 124         mutex_unlock(&thermal_hwmon_list_lock);
 125
 126         return NULL;
 127 }
 128
 129 static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
 130 {
 131         int temp;
 132         return tz->ops.get_crit_temp && !tz->ops.get_crit_temp(tz, &temp);
 133 }
 134
 135 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 136 {
 137         struct thermal_hwmon_device *hwmon;
 138         struct thermal_hwmon_temp *temp;
 139         int new_hwmon_device = 1;
 140         int result;
 141
 142         hwmon = thermal_hwmon_lookup_by_type(tz);
 143         if (hwmon) {
 144                 new_hwmon_device = 0;
 145                 goto register_sys_interface;
 146         }
 147
 148         hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
 149         if (!hwmon)
 150                 return -ENOMEM;
 151
 152         INIT_LIST_HEAD(&hwmon->tz_list);
 153         strscpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
 154         strreplace(hwmon->type, '-', '_');
 155         hwmon->device = hwmon_device_register_for_thermal(&tz->device,
 156                                                           hwmon->type, hwmon);
 157         if (IS_ERR(hwmon->device)) {
 158                 result = PTR_ERR(hwmon->device);
 159                 goto free_mem;
 160         }
 161
 162  register_sys_interface:
 163         temp = kzalloc(sizeof(*temp), GFP_KERNEL);
 164         if (!temp) {
 165                 result = -ENOMEM;
 166                 goto unregister_name;
 167         }
 168
 169         temp->tz = tz;
 170         hwmon->count++;
 171
 172         snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
 173                  "temp%d_input", hwmon->count);
 174         temp->temp_input.attr.attr.name = temp->temp_input.name;
 175         temp->temp_input.attr.attr.mode = 0444;
 176         temp->temp_input.attr.show = temp_input_show;
 177         sysfs_attr_init(&temp->temp_input.attr.attr);
 178         result = device_create_file(hwmon->device, &temp->temp_input.attr);
 179         if (result)
 180                 goto free_temp_mem;
 181
 182         if (thermal_zone_crit_temp_valid(tz)) {
 183                 snprintf(temp->temp_crit.name,
 184                                 sizeof(temp->temp_crit.name),
 185                                 "temp%d_crit", hwmon->count);
 186                 temp->temp_crit.attr.attr.name = temp->temp_crit.name;
 187                 temp->temp_crit.attr.attr.mode = 0444;
 188                 temp->temp_crit.attr.show = temp_crit_show;
 189                 sysfs_attr_init(&temp->temp_crit.attr.attr);
 190                 result = device_create_file(hwmon->device,
 191                                             &temp->temp_crit.attr);
 192                 if (result)
 193                         goto unregister_input;
 194         }
 195
 196         mutex_lock(&thermal_hwmon_list_lock);
 197         if (new_hwmon_device)
 198                 list_add_tail(&hwmon->node, &thermal_hwmon_list);
 199         list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
 200         mutex_unlock(&thermal_hwmon_list_lock);
 201
 202         return 0;
 203
 204  unregister_input:
 205         device_remove_file(hwmon->device, &temp->temp_input.attr);
 206  free_temp_mem:
 207         kfree(temp);
 208  unregister_name:
 209         if (new_hwmon_device)
 210                 hwmon_device_unregister(hwmon->device);
 211  free_mem:
 212         kfree(hwmon);
 213
 214         return result;
 215 }
 216 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 217
 218 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 219 {
 220         struct thermal_hwmon_device *hwmon;
 221         struct thermal_hwmon_temp *temp;
 222
 223         hwmon = thermal_hwmon_lookup_by_type(tz);
 224         if (unlikely(!hwmon)) {
 225                 /* Should never happen... */
 226                 dev_dbg(&tz->device, "hwmon device lookup failed!\n");
 227                 return;
 228         }
 229
 230         temp = thermal_hwmon_lookup_temp(hwmon, tz);
 231         if (unlikely(!temp)) {
 232                 /* Should never happen... */
 233                 dev_dbg(&tz->device, "temperature input lookup failed!\n");
 234                 return;
 235         }
 236
 237         device_remove_file(hwmon->device, &temp->temp_input.attr);
 238         if (thermal_zone_crit_temp_valid(tz))
 239                 device_remove_file(hwmon->device, &temp->temp_crit.attr);
 240
 241         mutex_lock(&thermal_hwmon_list_lock);
 242         list_del(&temp->hwmon_node);
 243         kfree(temp);
 244         if (!list_empty(&hwmon->tz_list)) {
 245                 mutex_unlock(&thermal_hwmon_list_lock);
 246                 return;
 247         }
 248         list_del(&hwmon->node);
 249         mutex_unlock(&thermal_hwmon_list_lock);
 250
 251         hwmon_device_unregister(hwmon->device);
 252         kfree(hwmon);
 253 }
 254 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);
 255
 256 static void devm_thermal_hwmon_release(struct device *dev, void *res)
 257 {
 258         thermal_remove_hwmon_sysfs(*(struct thermal_zone_device **)res);
 259 }
 260
 261 int devm_thermal_add_hwmon_sysfs(struct device *dev, struct thermal_zone_device *tz)
 262 {
 263         struct thermal_zone_device **ptr;
 264         int ret;
 265
 266         ptr = devres_alloc(devm_thermal_hwmon_release, sizeof(*ptr),
 267                            GFP_KERNEL);
 268         if (!ptr) {
 269                 dev_warn(dev, "Failed to allocate device resource data\n");
 270                 return -ENOMEM;
 271         }
 272
 273         ret = thermal_add_hwmon_sysfs(tz);
 274         if (ret) {
 275                 dev_warn(dev, "Failed to add hwmon sysfs attributes\n");
 276                 devres_free(ptr);
 277                 return ret;
 278         }
 279
 280         *ptr = tz;
 281         devres_add(dev, ptr);
 282
 283         return ret;
 284 }
 285 EXPORT_SYMBOL_GPL(devm_thermal_add_hwmon_sysfs);
 286
 287 MODULE_IMPORT_NS("HWMON_THERMAL");