LXR linux/drivers/thermal/thermal

   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 */
  23struct 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
  31struct thermal_hwmon_attr {
  32        struct device_attribute attr;
  33        char name[16];
  34};
  35
  36/* one temperature input for each thermal zone */
  37struct 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
  44static LIST_HEAD(thermal_hwmon_list);
  45
  46static DEFINE_MUTEX(thermal_hwmon_list_lock);
  47
  48static ssize_t
  49temp_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
  68static ssize_t
  69temp_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
  88static struct thermal_hwmon_device *
  89thermal_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 */
 109static struct thermal_hwmon_temp *
 110thermal_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
 126static 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
 132int 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_with_info(&tz->device, hwmon->type,
 153                                                        hwmon, NULL, NULL);
 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}
 213EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 214
 215void 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}
 251EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);
 252
 253static void devm_thermal_hwmon_release(struct device *dev, void *res)
 254{
 255        thermal_remove_hwmon_sysfs(*(struct thermal_zone_device **)res);
 256}
 257
 258int 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}
 279EXPORT_SYMBOL_GPL(devm_thermal_add_hwmon_sysfs);
 280