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 hwmon->device = hwmon_device_register_with_info(NULL, hwmon->type, 146 hwmon, NULL, NULL); 147 if (IS_ERR(hwmon->device)) { 148 result = PTR_ERR(hwmon->device); 149 goto free_mem; 150 } 151 152 register_sys_interface: 153 temp = kzalloc(sizeof(*temp), GFP_KERNEL); 154 if (!temp) { 155 result = -ENOMEM; 156 goto unregister_name; 157 } 158 159 temp->tz = tz; 160 hwmon->count++; 161 162 snprintf(temp->temp_input.name, sizeof(temp->temp_input.name), 163 "temp%d_input", hwmon->count); 164 temp->temp_input.attr.attr.name = temp->temp_input.name; 165 temp->temp_input.attr.attr.mode = 0444; 166 temp->temp_input.attr.show = temp_input_show; 167 sysfs_attr_init(&temp->temp_input.attr.attr); 168 result = device_create_file(hwmon->device, &temp->temp_input.attr); 169 if (result) 170 goto free_temp_mem; 171 172 if (thermal_zone_crit_temp_valid(tz)) { 173 snprintf(temp->temp_crit.name, 174 sizeof(temp->temp_crit.name), 175 "temp%d_crit", hwmon->count); 176 temp->temp_crit.attr.attr.name = temp->temp_crit.name; 177 temp->temp_crit.attr.attr.mode = 0444; 178 temp->temp_crit.attr.show = temp_crit_show; 179 sysfs_attr_init(&temp->temp_crit.attr.attr); 180 result = device_create_file(hwmon->device, 181 &temp->temp_crit.attr); 182 if (result) 183 goto unregister_input; 184 } 185 186 mutex_lock(&thermal_hwmon_list_lock); 187 if (new_hwmon_device) 188 list_add_tail(&hwmon->node, &thermal_hwmon_list); 189 list_add_tail(&temp->hwmon_node, &hwmon->tz_list); 190 mutex_unlock(&thermal_hwmon_list_lock); 191 192 return 0; 193 194 unregister_input: 195 device_remove_file(hwmon->device, &temp->temp_input.attr); 196 free_temp_mem: 197 kfree(temp); 198 unregister_name: 199 if (new_hwmon_device) 200 hwmon_device_unregister(hwmon->device); 201 free_mem: 202 if (new_hwmon_device) 203 kfree(hwmon); 204 205 return result; 206 } 207 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs); 208 209 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz) 210 { 211 struct thermal_hwmon_device *hwmon; 212 struct thermal_hwmon_temp *temp; 213 214 hwmon = thermal_hwmon_lookup_by_type(tz); 215 if (unlikely(!hwmon)) { 216 /* Should never happen... */ 217 dev_dbg(&tz->device, "hwmon device lookup failed!\n"); 218 return; 219 } 220 221 temp = thermal_hwmon_lookup_temp(hwmon, tz); 222 if (unlikely(!temp)) { 223 /* Should never happen... */ 224 dev_dbg(&tz->device, "temperature input lookup failed!\n"); 225 return; 226 } 227 228 device_remove_file(hwmon->device, &temp->temp_input.attr); 229 if (thermal_zone_crit_temp_valid(tz)) 230 device_remove_file(hwmon->device, &temp->temp_crit.attr); 231 232 mutex_lock(&thermal_hwmon_list_lock); 233 list_del(&temp->hwmon_node); 234 kfree(temp); 235 if (!list_empty(&hwmon->tz_list)) { 236 mutex_unlock(&thermal_hwmon_list_lock); 237 return; 238 } 239 list_del(&hwmon->node); 240 mutex_unlock(&thermal_hwmon_list_lock); 241 242 hwmon_device_unregister(hwmon->device); 243 kfree(hwmon); 244 } 245 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs); 246