1/*
2 *  thermal_hwmon.c - Generic Thermal Management hwmon support.
3 *
4 *  Code based on Intel thermal_core.c. Copyrights of the original code:
5 *  Copyright (C) 2008 Intel Corp
6 *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
7 *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
8 *
9 *  Copyright (C) 2013 Texas Instruments
10 *  Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
11 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
12 *
13 *  This program is free software; you can redistribute it and/or modify
14 *  it under the terms of the GNU General Public License as published by
15 *  the Free Software Foundation; version 2 of the License.
16 *
17 *  This program is distributed in the hope that it will be useful, but
18 *  WITHOUT ANY WARRANTY; without even the implied warranty of
19 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20 *  General Public License for more details.
21 *
22 *  You should have received a copy of the GNU General Public License along
23 *  with this program; if not, write to the Free Software Foundation, Inc.,
24 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25 *
26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
27 */
28#include <linux/hwmon.h>
29#include <linux/thermal.h>
30#include <linux/slab.h>
31#include <linux/err.h>
32#include "thermal_hwmon.h"
33
34/* hwmon sys I/F */
35/* thermal zone devices with the same type share one hwmon device */
36struct thermal_hwmon_device {
37	char type[THERMAL_NAME_LENGTH];
38	struct device *device;
39	int count;
40	struct list_head tz_list;
41	struct list_head node;
42};
43
44struct thermal_hwmon_attr {
45	struct device_attribute attr;
46	char name[16];
47};
48
49/* one temperature input for each thermal zone */
50struct thermal_hwmon_temp {
51	struct list_head hwmon_node;
52	struct thermal_zone_device *tz;
53	struct thermal_hwmon_attr temp_input;	/* hwmon sys attr */
54	struct thermal_hwmon_attr temp_crit;	/* hwmon sys attr */
55};
56
57static LIST_HEAD(thermal_hwmon_list);
58
59static DEFINE_MUTEX(thermal_hwmon_list_lock);
60
61static ssize_t
62name_show(struct device *dev, struct device_attribute *attr, char *buf)
63{
64	struct thermal_hwmon_device *hwmon = dev_get_drvdata(dev);
65	return sprintf(buf, "%s\n", hwmon->type);
66}
67static DEVICE_ATTR(name, 0444, name_show, NULL);
68
69static ssize_t
70temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
71{
72	int temperature;
73	int ret;
74	struct thermal_hwmon_attr *hwmon_attr
75			= container_of(attr, struct thermal_hwmon_attr, attr);
76	struct thermal_hwmon_temp *temp
77			= container_of(hwmon_attr, struct thermal_hwmon_temp,
78				       temp_input);
79	struct thermal_zone_device *tz = temp->tz;
80
81	ret = thermal_zone_get_temp(tz, &temperature);
82
83	if (ret)
84		return ret;
85
86	return sprintf(buf, "%d\n", temperature);
87}
88
89static ssize_t
90temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
91{
92	struct thermal_hwmon_attr *hwmon_attr
93			= container_of(attr, struct thermal_hwmon_attr, attr);
94	struct thermal_hwmon_temp *temp
95			= container_of(hwmon_attr, struct thermal_hwmon_temp,
96				       temp_crit);
97	struct thermal_zone_device *tz = temp->tz;
98	int temperature;
99	int ret;
100
101	ret = tz->ops->get_trip_temp(tz, 0, &temperature);
102	if (ret)
103		return ret;
104
105	return sprintf(buf, "%d\n", temperature);
106}
107
108
109static struct thermal_hwmon_device *
110thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
111{
112	struct thermal_hwmon_device *hwmon;
113
114	mutex_lock(&thermal_hwmon_list_lock);
115	list_for_each_entry(hwmon, &thermal_hwmon_list, node)
116		if (!strcmp(hwmon->type, tz->type)) {
117			mutex_unlock(&thermal_hwmon_list_lock);
118			return hwmon;
119		}
120	mutex_unlock(&thermal_hwmon_list_lock);
121
122	return NULL;
123}
124
125/* Find the temperature input matching a given thermal zone */
126static struct thermal_hwmon_temp *
127thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
128			  const struct thermal_zone_device *tz)
129{
130	struct thermal_hwmon_temp *temp;
131
132	mutex_lock(&thermal_hwmon_list_lock);
133	list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
134		if (temp->tz == tz) {
135			mutex_unlock(&thermal_hwmon_list_lock);
136			return temp;
137		}
138	mutex_unlock(&thermal_hwmon_list_lock);
139
140	return NULL;
141}
142
143static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
144{
145	int temp;
146	return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
147}
148
149int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
150{
151	struct thermal_hwmon_device *hwmon;
152	struct thermal_hwmon_temp *temp;
153	int new_hwmon_device = 1;
154	int result;
155
156	hwmon = thermal_hwmon_lookup_by_type(tz);
157	if (hwmon) {
158		new_hwmon_device = 0;
159		goto register_sys_interface;
160	}
161
162	hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
163	if (!hwmon)
164		return -ENOMEM;
165
166	INIT_LIST_HEAD(&hwmon->tz_list);
167	strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
168	hwmon->device = hwmon_device_register(NULL);
169	if (IS_ERR(hwmon->device)) {
170		result = PTR_ERR(hwmon->device);
171		goto free_mem;
172	}
173	dev_set_drvdata(hwmon->device, hwmon);
174	result = device_create_file(hwmon->device, &dev_attr_name);
175	if (result)
176		goto free_mem;
177
178 register_sys_interface:
179	temp = kzalloc(sizeof(*temp), GFP_KERNEL);
180	if (!temp) {
181		result = -ENOMEM;
182		goto unregister_name;
183	}
184
185	temp->tz = tz;
186	hwmon->count++;
187
188	snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
189		 "temp%d_input", hwmon->count);
190	temp->temp_input.attr.attr.name = temp->temp_input.name;
191	temp->temp_input.attr.attr.mode = 0444;
192	temp->temp_input.attr.show = temp_input_show;
193	sysfs_attr_init(&temp->temp_input.attr.attr);
194	result = device_create_file(hwmon->device, &temp->temp_input.attr);
195	if (result)
196		goto free_temp_mem;
197
198	if (thermal_zone_crit_temp_valid(tz)) {
199		snprintf(temp->temp_crit.name,
200				sizeof(temp->temp_crit.name),
201				"temp%d_crit", hwmon->count);
202		temp->temp_crit.attr.attr.name = temp->temp_crit.name;
203		temp->temp_crit.attr.attr.mode = 0444;
204		temp->temp_crit.attr.show = temp_crit_show;
205		sysfs_attr_init(&temp->temp_crit.attr.attr);
206		result = device_create_file(hwmon->device,
207					    &temp->temp_crit.attr);
208		if (result)
209			goto unregister_input;
210	}
211
212	mutex_lock(&thermal_hwmon_list_lock);
213	if (new_hwmon_device)
214		list_add_tail(&hwmon->node, &thermal_hwmon_list);
215	list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
216	mutex_unlock(&thermal_hwmon_list_lock);
217
218	return 0;
219
220 unregister_input:
221	device_remove_file(hwmon->device, &temp->temp_input.attr);
222 free_temp_mem:
223	kfree(temp);
224 unregister_name:
225	if (new_hwmon_device) {
226		device_remove_file(hwmon->device, &dev_attr_name);
227		hwmon_device_unregister(hwmon->device);
228	}
229 free_mem:
230	if (new_hwmon_device)
231		kfree(hwmon);
232
233	return result;
234}
235
236void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
237{
238	struct thermal_hwmon_device *hwmon;
239	struct thermal_hwmon_temp *temp;
240
241	hwmon = thermal_hwmon_lookup_by_type(tz);
242	if (unlikely(!hwmon)) {
243		/* Should never happen... */
244		dev_dbg(&tz->device, "hwmon device lookup failed!\n");
245		return;
246	}
247
248	temp = thermal_hwmon_lookup_temp(hwmon, tz);
249	if (unlikely(!temp)) {
250		/* Should never happen... */
251		dev_dbg(&tz->device, "temperature input lookup failed!\n");
252		return;
253	}
254
255	device_remove_file(hwmon->device, &temp->temp_input.attr);
256	if (thermal_zone_crit_temp_valid(tz))
257		device_remove_file(hwmon->device, &temp->temp_crit.attr);
258
259	mutex_lock(&thermal_hwmon_list_lock);
260	list_del(&temp->hwmon_node);
261	kfree(temp);
262	if (!list_empty(&hwmon->tz_list)) {
263		mutex_unlock(&thermal_hwmon_list_lock);
264		return;
265	}
266	list_del(&hwmon->node);
267	mutex_unlock(&thermal_hwmon_list_lock);
268
269	device_remove_file(hwmon->device, &dev_attr_name);
270	hwmon_device_unregister(hwmon->device);
271	kfree(hwmon);
272}
273