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
temp_input_show(struct device * dev,struct device_attribute * attr,char * buf)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
temp_crit_show(struct device * dev,struct device_attribute * attr,char * buf)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 *
thermal_hwmon_lookup_by_type(const struct thermal_zone_device * tz)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 *
thermal_hwmon_lookup_temp(const struct thermal_hwmon_device * hwmon,const struct thermal_zone_device * tz)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
thermal_zone_crit_temp_valid(struct thermal_zone_device * tz)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
thermal_add_hwmon_sysfs(struct thermal_zone_device * tz)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
thermal_remove_hwmon_sysfs(struct thermal_zone_device * tz)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);
251