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/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 */
  21struct 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
  29struct thermal_hwmon_attr {
  30        struct device_attribute attr;
  31        char name[16];
  32};
  33
  34/* one temperature input for each thermal zone */
  35struct 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
  42static LIST_HEAD(thermal_hwmon_list);
  43
  44static DEFINE_MUTEX(thermal_hwmon_list_lock);
  45
  46static ssize_t
  47temp_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
  66static ssize_t
  67temp_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
  86static struct thermal_hwmon_device *
  87thermal_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 */
 103static struct thermal_hwmon_temp *
 104thermal_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
 120static 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
 126int 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(&tz->device, 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}
 208EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
 209
 210void 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}
 246EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);
 247