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 #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         ret = tz->ops.get_crit_temp(tz, &temperature);
  84
  85         mutex_unlock(&tz->lock);
  86
  87         if (ret)
  88                 return ret;
  89
  90         return sprintf(buf, "%d\n", temperature);
  91 }
  92
  93
  94 static struct thermal_hwmon_device *
  95 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
  96 {
  97         struct thermal_hwmon_device *hwmon;
  98         char type[THERMAL_NAME_LENGTH];
  99
 100         mutex_lock(&thermal_hwmon_list_lock);
 101         list_for_each_entry(hwmon, &thermal_hwmon_list, node) {
 102                 strcpy(type, tz->type);
 103                 strreplace(type, '-', '_');
 104                 if (!strcmp(hwmon->type, type)) {
 105                         mutex_unlock(&thermal_hwmon_list_lock);
 106                         return hwmon;
 107                 }
 108         }
 109         mutex_unlock(&thermal_hwmon_list_lock);
 110
 111         return NULL;
 112 }
 113
 114 /* Find the temperature input matching a given thermal zone */
 115 static struct thermal_hwmon_temp *
 116 thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
 117                           const struct thermal_zone_device *tz)
 118 {
 119         struct thermal_hwmon_temp *temp;
 120
 121         mutex_lock(&thermal_hwmon_list_lock);
 122         list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
 123                 if (temp->tz == tz) {
 124                         mutex_unlock(&thermal_hwmon_list_lock);
 125                         return temp;
 126                 }
 127         mutex_unlock(&thermal_hwmon_list_lock);
 128
 129         return NULL;
 130 }
 131
 132 static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
 133 {
 134         int temp;
 135         return tz->ops.get_crit_temp && !tz->ops.get_crit_temp(tz, &temp);
 136 }
 137
 138 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 139 {
 140         struct thermal_hwmon_device *hwmon;
 141         struct thermal_hwmon_temp *temp;
 142         int new_hwmon_device = 1;
 143         int result;
 144
 145         hwmon = thermal_hwmon_lookup_by_type(tz);
 146         if (hwmon) {
 147                 new_hwmon_device = 0;
 148                 goto register_sys_interface;
 149         }
 150
 151         hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
 152         if (!hwmon)
 153                 return -ENOMEM;
 154
 155         INIT_LIST_HEAD(&hwmon->tz_list);
 156         strscpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
 157         strreplace(hwmon->type, '-', '_');
 158         hwmon->device = hwmon_device_register_for_thermal(&tz->device,
 159                                                           hwmon->type, hwmon);
 160         if (IS_ERR(hwmon->device)) {
 161                 result = PTR_ERR(hwmon->device);
 162                 goto free_mem;
 163         }
 164
 165  register_sys_interface:
 166         temp = kzalloc(sizeof(*temp), GFP_KERNEL);
 167         if (!temp) {
 168                 result = -ENOMEM;
 169                 goto unregister_name;
 170         }
 171
 172         temp->tz = tz;
 173         hwmon->count++;
 174
 175         snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
 176                  "temp%d_input", hwmon->count);
 177         temp->temp_input.attr.attr.name = temp->temp_input.name;
 178         temp->temp_input.attr.attr.mode = 0444;
 179         temp->temp_input.attr.show = temp_input_show;
 180         sysfs_attr_init(&temp->temp_input.attr.attr);
 181         result = device_create_file(hwmon->device, &temp->temp_input.attr);
 182         if (result)
 183                 goto free_temp_mem;
 184
 185         if (thermal_zone_crit_temp_valid(tz)) {
 186                 snprintf(temp->temp_crit.name,
 187                                 sizeof(temp->temp_crit.name),
 188                                 "temp%d_crit", hwmon->count);
 189                 temp->temp_crit.attr.attr.name = temp->temp_crit.name;
 190                 temp->temp_crit.attr.attr.mode = 0444;
 191                 temp->temp_crit.attr.show = temp_crit_show;
 192                 sysfs_attr_init(&temp->temp_crit.attr.attr);
 193                 result = device_create_file(hwmon->device,
 194                                             &temp->temp_crit.attr);
 195                 if (result)
 196                         goto unregister_input;
 197         }
 198
 199         mutex_lock(&thermal_hwmon_list_lock);
 200         if (new_hwmon_device)
 201                 list_add_tail(&hwmon->node, &thermal_hwmon_list);
 202         list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
 203         mutex_unlock(&thermal_hwmon_list_lock);
 204
 205         return 0;
 206
 207  unregister_input:
 208         device_remove_file(hwmon->device, &temp->temp_input.attr);
 209  free_temp_mem:
 210         kfree(temp);
 211  unregister_name:
 212         if (new_hwmon_device)
 213                 hwmon_device_unregister(hwmon->device);
 214  free_mem:
 215         kfree(hwmon);
 216
 217         return result;
 218 }
 219 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 220
 221 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 222 {
 223         struct thermal_hwmon_device *hwmon;
 224         struct thermal_hwmon_temp *temp;
 225
 226         hwmon = thermal_hwmon_lookup_by_type(tz);
 227         if (unlikely(!hwmon)) {
 228                 /* Should never happen... */
 229                 dev_dbg(&tz->device, "hwmon device lookup failed!\n");
 230                 return;
 231         }
 232
 233         temp = thermal_hwmon_lookup_temp(hwmon, tz);
 234         if (unlikely(!temp)) {
 235                 /* Should never happen... */
 236                 dev_dbg(&tz->device, "temperature input lookup failed!\n");
 237                 return;
 238         }
 239
 240         device_remove_file(hwmon->device, &temp->temp_input.attr);
 241         if (thermal_zone_crit_temp_valid(tz))
 242                 device_remove_file(hwmon->device, &temp->temp_crit.attr);
 243
 244         mutex_lock(&thermal_hwmon_list_lock);
 245         list_del(&temp->hwmon_node);
 246         kfree(temp);
 247         if (!list_empty(&hwmon->tz_list)) {
 248                 mutex_unlock(&thermal_hwmon_list_lock);
 249                 return;
 250         }
 251         list_del(&hwmon->node);
 252         mutex_unlock(&thermal_hwmon_list_lock);
 253
 254         hwmon_device_unregister(hwmon->device);
 255         kfree(hwmon);
 256 }
 257 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);
 258
 259 static void devm_thermal_hwmon_release(struct device *dev, void *res)
 260 {
 261         thermal_remove_hwmon_sysfs(*(struct thermal_zone_device **)res);
 262 }
 263
 264 int devm_thermal_add_hwmon_sysfs(struct device *dev, struct thermal_zone_device *tz)
 265 {
 266         struct thermal_zone_device **ptr;
 267         int ret;
 268
 269         ptr = devres_alloc(devm_thermal_hwmon_release, sizeof(*ptr),
 270                            GFP_KERNEL);
 271         if (!ptr) {
 272                 dev_warn(dev, "Failed to allocate device resource data\n");
 273                 return -ENOMEM;
 274         }
 275
 276         ret = thermal_add_hwmon_sysfs(tz);
 277         if (ret) {
 278                 dev_warn(dev, "Failed to add hwmon sysfs attributes\n");
 279                 devres_free(ptr);
 280                 return ret;
 281         }
 282
 283         *ptr = tz;
 284         devres_add(dev, ptr);
 285
 286         return ret;
 287 }
 288 EXPORT_SYMBOL_GPL(devm_thermal_add_hwmon_sysfs);
 289
 290 MODULE_IMPORT_NS(HWMON_THERMAL);