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/hwmon.h>
  14 #include <linux/thermal.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include "thermal_hwmon.h"
  18
  19 /* hwmon sys I/F */
  20 /* thermal zone devices with the same type share one hwmon device */
  21 struct thermal_hwmon_device {
  22         char type[THERMAL_NAME_LENGTH];
  23         struct device *device;
  24         int count;
  25         struct list_head tz_list;
  26         struct list_head node;
  27 };
  28
  29 struct thermal_hwmon_attr {
  30         struct device_attribute attr;
  31         char name[16];
  32 };
  33
  34 /* one temperature input for each thermal zone */
  35 struct thermal_hwmon_temp {
  36         struct list_head hwmon_node;
  37         struct thermal_zone_device *tz;
  38         struct thermal_hwmon_attr temp_input;   /* hwmon sys attr */
  39         struct thermal_hwmon_attr temp_crit;    /* hwmon sys attr */
  40 };
  41
  42 static LIST_HEAD(thermal_hwmon_list);
  43
  44 static DEFINE_MUTEX(thermal_hwmon_list_lock);
  45
  46 static ssize_t
  47 temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
  48 {
  49         int temperature;
  50         int ret;
  51         struct thermal_hwmon_attr *hwmon_attr
  52                         = container_of(attr, struct thermal_hwmon_attr, attr);
  53         struct thermal_hwmon_temp *temp
  54                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  55                                        temp_input);
  56         struct thermal_zone_device *tz = temp->tz;
  57
  58         ret = thermal_zone_get_temp(tz, &temperature);
  59
  60         if (ret)
  61                 return ret;
  62
  63         return sprintf(buf, "%d\n", temperature);
  64 }
  65
  66 static ssize_t
  67 temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
  68 {
  69         struct thermal_hwmon_attr *hwmon_attr
  70                         = container_of(attr, struct thermal_hwmon_attr, attr);
  71         struct thermal_hwmon_temp *temp
  72                         = container_of(hwmon_attr, struct thermal_hwmon_temp,
  73                                        temp_crit);
  74         struct thermal_zone_device *tz = temp->tz;
  75         int temperature;
  76         int ret;
  77
  78         ret = tz->ops->get_crit_temp(tz, &temperature);
  79         if (ret)
  80                 return ret;
  81
  82         return sprintf(buf, "%d\n", temperature);
  83 }
  84
  85
  86 static struct thermal_hwmon_device *
  87 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
  88 {
  89         struct thermal_hwmon_device *hwmon;
  90         char type[THERMAL_NAME_LENGTH];
  91
  92         mutex_lock(&thermal_hwmon_list_lock);
  93         list_for_each_entry(hwmon, &thermal_hwmon_list, node) {
  94                 strcpy(type, tz->type);
  95                 strreplace(type, '-', '_');
  96                 if (!strcmp(hwmon->type, type)) {
  97                         mutex_unlock(&thermal_hwmon_list_lock);
  98                         return hwmon;
  99                 }
 100         }
 101         mutex_unlock(&thermal_hwmon_list_lock);
 102
 103         return NULL;
 104 }
 105
 106 /* Find the temperature input matching a given thermal zone */
 107 static struct thermal_hwmon_temp *
 108 thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
 109                           const struct thermal_zone_device *tz)
 110 {
 111         struct thermal_hwmon_temp *temp;
 112
 113         mutex_lock(&thermal_hwmon_list_lock);
 114         list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
 115                 if (temp->tz == tz) {
 116                         mutex_unlock(&thermal_hwmon_list_lock);
 117                         return temp;
 118                 }
 119         mutex_unlock(&thermal_hwmon_list_lock);
 120
 121         return NULL;
 122 }
 123
 124 static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
 125 {
 126         int temp;
 127         return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
 128 }
 129
 130 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
 131 {
 132         struct thermal_hwmon_device *hwmon;
 133         struct thermal_hwmon_temp *temp;
 134         int new_hwmon_device = 1;
 135         int result;
 136
 137         hwmon = thermal_hwmon_lookup_by_type(tz);
 138         if (hwmon) {
 139                 new_hwmon_device = 0;
 140                 goto register_sys_interface;
 141         }
 142
 143         hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
 144         if (!hwmon)
 145                 return -ENOMEM;
 146
 147         INIT_LIST_HEAD(&hwmon->tz_list);
 148         strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
 149         strreplace(hwmon->type, '-', '_');
 150         hwmon->device = hwmon_device_register_with_info(&tz->device, hwmon->type,
 151                                                         hwmon, NULL, NULL);
 152         if (IS_ERR(hwmon->device)) {
 153                 result = PTR_ERR(hwmon->device);
 154                 goto free_mem;
 155         }
 156
 157  register_sys_interface:
 158         temp = kzalloc(sizeof(*temp), GFP_KERNEL);
 159         if (!temp) {
 160                 result = -ENOMEM;
 161                 goto unregister_name;
 162         }
 163
 164         temp->tz = tz;
 165         hwmon->count++;
 166
 167         snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
 168                  "temp%d_input", hwmon->count);
 169         temp->temp_input.attr.attr.name = temp->temp_input.name;
 170         temp->temp_input.attr.attr.mode = 0444;
 171         temp->temp_input.attr.show = temp_input_show;
 172         sysfs_attr_init(&temp->temp_input.attr.attr);
 173         result = device_create_file(hwmon->device, &temp->temp_input.attr);
 174         if (result)
 175                 goto free_temp_mem;
 176
 177         if (thermal_zone_crit_temp_valid(tz)) {
 178                 snprintf(temp->temp_crit.name,
 179                                 sizeof(temp->temp_crit.name),
 180                                 "temp%d_crit", hwmon->count);
 181                 temp->temp_crit.attr.attr.name = temp->temp_crit.name;
 182                 temp->temp_crit.attr.attr.mode = 0444;
 183                 temp->temp_crit.attr.show = temp_crit_show;
 184                 sysfs_attr_init(&temp->temp_crit.attr.attr);
 185                 result = device_create_file(hwmon->device,
 186                                             &temp->temp_crit.attr);
 187                 if (result)
 188                         goto unregister_input;
 189         }
 190
 191         mutex_lock(&thermal_hwmon_list_lock);
 192         if (new_hwmon_device)
 193                 list_add_tail(&hwmon->node, &thermal_hwmon_list);
 194         list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
 195         mutex_unlock(&thermal_hwmon_list_lock);
 196
 197         return 0;
 198
 199  unregister_input:
 200         device_remove_file(hwmon->device, &temp->temp_input.attr);
 201  free_temp_mem:
 202         kfree(temp);
 203  unregister_name:
 204         if (new_hwmon_device)
 205                 hwmon_device_unregister(hwmon->device);
 206  free_mem:
 207         if (new_hwmon_device)
 208                 kfree(hwmon);
 209
 210         return result;
 211 }
 212 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 213
 214 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
 215 {
 216         struct thermal_hwmon_device *hwmon;
 217         struct thermal_hwmon_temp *temp;
 218
 219         hwmon = thermal_hwmon_lookup_by_type(tz);
 220         if (unlikely(!hwmon)) {
 221                 /* Should never happen... */
 222                 dev_dbg(&tz->device, "hwmon device lookup failed!\n");
 223                 return;
 224         }
 225
 226         temp = thermal_hwmon_lookup_temp(hwmon, tz);
 227         if (unlikely(!temp)) {
 228                 /* Should never happen... */
 229                 dev_dbg(&tz->device, "temperature input lookup failed!\n");
 230                 return;
 231         }
 232
 233         device_remove_file(hwmon->device, &temp->temp_input.attr);
 234         if (thermal_zone_crit_temp_valid(tz))
 235                 device_remove_file(hwmon->device, &temp->temp_crit.attr);
 236
 237         mutex_lock(&thermal_hwmon_list_lock);
 238         list_del(&temp->hwmon_node);
 239         kfree(temp);
 240         if (!list_empty(&hwmon->tz_list)) {
 241                 mutex_unlock(&thermal_hwmon_list_lock);
 242                 return;
 243         }
 244         list_del(&hwmon->node);
 245         mutex_unlock(&thermal_hwmon_list_lock);
 246
 247         hwmon_device_unregister(hwmon->device);
 248         kfree(hwmon);
 249 }
 250 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);