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