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 	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 *
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 
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 
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 
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