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