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 #include "thermal_core.h"
21 
22 /* hwmon sys I/F */
23 /* thermal zone devices with the same type share one hwmon device */
24 struct thermal_hwmon_device {
25 	char type[THERMAL_NAME_LENGTH];
26 	struct device *device;
27 	int count;
28 	struct list_head tz_list;
29 	struct list_head node;
30 };
31 
32 struct thermal_hwmon_attr {
33 	struct device_attribute attr;
34 	char name[16];
35 };
36 
37 /* one temperature input for each thermal zone */
38 struct thermal_hwmon_temp {
39 	struct list_head hwmon_node;
40 	struct thermal_zone_device *tz;
41 	struct thermal_hwmon_attr temp_input;	/* hwmon sys attr */
42 	struct thermal_hwmon_attr temp_crit;	/* hwmon sys attr */
43 };
44 
45 static LIST_HEAD(thermal_hwmon_list);
46 
47 static DEFINE_MUTEX(thermal_hwmon_list_lock);
48 
49 static ssize_t
50 temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
51 {
52 	int temperature;
53 	int ret;
54 	struct thermal_hwmon_attr *hwmon_attr
55 			= container_of(attr, struct thermal_hwmon_attr, attr);
56 	struct thermal_hwmon_temp *temp
57 			= container_of(hwmon_attr, struct thermal_hwmon_temp,
58 				       temp_input);
59 	struct thermal_zone_device *tz = temp->tz;
60 
61 	ret = thermal_zone_get_temp(tz, &temperature);
62 
63 	if (ret)
64 		return ret;
65 
66 	return sprintf(buf, "%d\n", temperature);
67 }
68 
69 static ssize_t
70 temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
71 {
72 	struct thermal_hwmon_attr *hwmon_attr
73 			= container_of(attr, struct thermal_hwmon_attr, attr);
74 	struct thermal_hwmon_temp *temp
75 			= container_of(hwmon_attr, struct thermal_hwmon_temp,
76 				       temp_crit);
77 	struct thermal_zone_device *tz = temp->tz;
78 	int temperature;
79 	int ret;
80 
81 	mutex_lock(&tz->lock);
82 
83 	if (device_is_registered(&tz->device))
84 		ret = tz->ops->get_crit_temp(tz, &temperature);
85 	else
86 		ret = -ENODEV;
87 
88 	mutex_unlock(&tz->lock);
89 
90 	if (ret)
91 		return ret;
92 
93 	return sprintf(buf, "%d\n", temperature);
94 }
95 
96 
97 static struct thermal_hwmon_device *
98 thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
99 {
100 	struct thermal_hwmon_device *hwmon;
101 	char type[THERMAL_NAME_LENGTH];
102 
103 	mutex_lock(&thermal_hwmon_list_lock);
104 	list_for_each_entry(hwmon, &thermal_hwmon_list, node) {
105 		strcpy(type, tz->type);
106 		strreplace(type, '-', '_');
107 		if (!strcmp(hwmon->type, type)) {
108 			mutex_unlock(&thermal_hwmon_list_lock);
109 			return hwmon;
110 		}
111 	}
112 	mutex_unlock(&thermal_hwmon_list_lock);
113 
114 	return NULL;
115 }
116 
117 /* Find the temperature input matching a given thermal zone */
118 static struct thermal_hwmon_temp *
119 thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
120 			  const struct thermal_zone_device *tz)
121 {
122 	struct thermal_hwmon_temp *temp;
123 
124 	mutex_lock(&thermal_hwmon_list_lock);
125 	list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
126 		if (temp->tz == tz) {
127 			mutex_unlock(&thermal_hwmon_list_lock);
128 			return temp;
129 		}
130 	mutex_unlock(&thermal_hwmon_list_lock);
131 
132 	return NULL;
133 }
134 
135 static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
136 {
137 	int temp;
138 	return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
139 }
140 
141 int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
142 {
143 	struct thermal_hwmon_device *hwmon;
144 	struct thermal_hwmon_temp *temp;
145 	int new_hwmon_device = 1;
146 	int result;
147 
148 	hwmon = thermal_hwmon_lookup_by_type(tz);
149 	if (hwmon) {
150 		new_hwmon_device = 0;
151 		goto register_sys_interface;
152 	}
153 
154 	hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
155 	if (!hwmon)
156 		return -ENOMEM;
157 
158 	INIT_LIST_HEAD(&hwmon->tz_list);
159 	strscpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
160 	strreplace(hwmon->type, '-', '_');
161 	hwmon->device = hwmon_device_register_for_thermal(&tz->device,
162 							  hwmon->type, hwmon);
163 	if (IS_ERR(hwmon->device)) {
164 		result = PTR_ERR(hwmon->device);
165 		goto free_mem;
166 	}
167 
168  register_sys_interface:
169 	temp = kzalloc(sizeof(*temp), GFP_KERNEL);
170 	if (!temp) {
171 		result = -ENOMEM;
172 		goto unregister_name;
173 	}
174 
175 	temp->tz = tz;
176 	hwmon->count++;
177 
178 	snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
179 		 "temp%d_input", hwmon->count);
180 	temp->temp_input.attr.attr.name = temp->temp_input.name;
181 	temp->temp_input.attr.attr.mode = 0444;
182 	temp->temp_input.attr.show = temp_input_show;
183 	sysfs_attr_init(&temp->temp_input.attr.attr);
184 	result = device_create_file(hwmon->device, &temp->temp_input.attr);
185 	if (result)
186 		goto free_temp_mem;
187 
188 	if (thermal_zone_crit_temp_valid(tz)) {
189 		snprintf(temp->temp_crit.name,
190 				sizeof(temp->temp_crit.name),
191 				"temp%d_crit", hwmon->count);
192 		temp->temp_crit.attr.attr.name = temp->temp_crit.name;
193 		temp->temp_crit.attr.attr.mode = 0444;
194 		temp->temp_crit.attr.show = temp_crit_show;
195 		sysfs_attr_init(&temp->temp_crit.attr.attr);
196 		result = device_create_file(hwmon->device,
197 					    &temp->temp_crit.attr);
198 		if (result)
199 			goto unregister_input;
200 	}
201 
202 	mutex_lock(&thermal_hwmon_list_lock);
203 	if (new_hwmon_device)
204 		list_add_tail(&hwmon->node, &thermal_hwmon_list);
205 	list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
206 	mutex_unlock(&thermal_hwmon_list_lock);
207 
208 	return 0;
209 
210  unregister_input:
211 	device_remove_file(hwmon->device, &temp->temp_input.attr);
212  free_temp_mem:
213 	kfree(temp);
214  unregister_name:
215 	if (new_hwmon_device)
216 		hwmon_device_unregister(hwmon->device);
217  free_mem:
218 	kfree(hwmon);
219 
220 	return result;
221 }
222 EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
223 
224 void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
225 {
226 	struct thermal_hwmon_device *hwmon;
227 	struct thermal_hwmon_temp *temp;
228 
229 	hwmon = thermal_hwmon_lookup_by_type(tz);
230 	if (unlikely(!hwmon)) {
231 		/* Should never happen... */
232 		dev_dbg(&tz->device, "hwmon device lookup failed!\n");
233 		return;
234 	}
235 
236 	temp = thermal_hwmon_lookup_temp(hwmon, tz);
237 	if (unlikely(!temp)) {
238 		/* Should never happen... */
239 		dev_dbg(&tz->device, "temperature input lookup failed!\n");
240 		return;
241 	}
242 
243 	device_remove_file(hwmon->device, &temp->temp_input.attr);
244 	if (thermal_zone_crit_temp_valid(tz))
245 		device_remove_file(hwmon->device, &temp->temp_crit.attr);
246 
247 	mutex_lock(&thermal_hwmon_list_lock);
248 	list_del(&temp->hwmon_node);
249 	kfree(temp);
250 	if (!list_empty(&hwmon->tz_list)) {
251 		mutex_unlock(&thermal_hwmon_list_lock);
252 		return;
253 	}
254 	list_del(&hwmon->node);
255 	mutex_unlock(&thermal_hwmon_list_lock);
256 
257 	hwmon_device_unregister(hwmon->device);
258 	kfree(hwmon);
259 }
260 EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);
261 
262 static void devm_thermal_hwmon_release(struct device *dev, void *res)
263 {
264 	thermal_remove_hwmon_sysfs(*(struct thermal_zone_device **)res);
265 }
266 
267 int devm_thermal_add_hwmon_sysfs(struct device *dev, struct thermal_zone_device *tz)
268 {
269 	struct thermal_zone_device **ptr;
270 	int ret;
271 
272 	ptr = devres_alloc(devm_thermal_hwmon_release, sizeof(*ptr),
273 			   GFP_KERNEL);
274 	if (!ptr)
275 		return -ENOMEM;
276 
277 	ret = thermal_add_hwmon_sysfs(tz);
278 	if (ret) {
279 		devres_free(ptr);
280 		return ret;
281 	}
282 
283 	*ptr = tz;
284 	devres_add(dev, ptr);
285 
286 	return ret;
287 }
288 EXPORT_SYMBOL_GPL(devm_thermal_add_hwmon_sysfs);
289 
290 MODULE_IMPORT_NS(HWMON_THERMAL);
291