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  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
 62temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
 63{
 64	int temperature;
 65	int ret;
 66	struct thermal_hwmon_attr *hwmon_attr
 67			= container_of(attr, struct thermal_hwmon_attr, attr);
 68	struct thermal_hwmon_temp *temp
 69			= container_of(hwmon_attr, struct thermal_hwmon_temp,
 70				       temp_input);
 71	struct thermal_zone_device *tz = temp->tz;
 72
 73	ret = thermal_zone_get_temp(tz, &temperature);
 74
 75	if (ret)
 76		return ret;
 77
 78	return sprintf(buf, "%d\n", temperature);
 79}
 80
 81static ssize_t
 82temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
 83{
 84	struct thermal_hwmon_attr *hwmon_attr
 85			= container_of(attr, struct thermal_hwmon_attr, attr);
 86	struct thermal_hwmon_temp *temp
 87			= container_of(hwmon_attr, struct thermal_hwmon_temp,
 88				       temp_crit);
 89	struct thermal_zone_device *tz = temp->tz;
 90	int temperature;
 91	int ret;
 92
 93	ret = tz->ops->get_crit_temp(tz, &temperature);
 94	if (ret)
 95		return ret;
 96
 97	return sprintf(buf, "%d\n", temperature);
 98}
 99
100
101static struct thermal_hwmon_device *
102thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
103{
104	struct thermal_hwmon_device *hwmon;
105
106	mutex_lock(&thermal_hwmon_list_lock);
107	list_for_each_entry(hwmon, &thermal_hwmon_list, node)
108		if (!strcmp(hwmon->type, tz->type)) {
109			mutex_unlock(&thermal_hwmon_list_lock);
110			return hwmon;
111		}
112	mutex_unlock(&thermal_hwmon_list_lock);
113
114	return NULL;
115}
116
117/* Find the temperature input matching a given thermal zone */
118static struct thermal_hwmon_temp *
119thermal_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
135static 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
141int 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	strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
160	hwmon->device = hwmon_device_register_with_info(NULL, hwmon->type,
161							hwmon, NULL, NULL);
162	if (IS_ERR(hwmon->device)) {
163		result = PTR_ERR(hwmon->device);
164		goto free_mem;
165	}
166
167 register_sys_interface:
168	temp = kzalloc(sizeof(*temp), GFP_KERNEL);
169	if (!temp) {
170		result = -ENOMEM;
171		goto unregister_name;
172	}
173
174	temp->tz = tz;
175	hwmon->count++;
176
177	snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
178		 "temp%d_input", hwmon->count);
179	temp->temp_input.attr.attr.name = temp->temp_input.name;
180	temp->temp_input.attr.attr.mode = 0444;
181	temp->temp_input.attr.show = temp_input_show;
182	sysfs_attr_init(&temp->temp_input.attr.attr);
183	result = device_create_file(hwmon->device, &temp->temp_input.attr);
184	if (result)
185		goto free_temp_mem;
186
187	if (thermal_zone_crit_temp_valid(tz)) {
188		snprintf(temp->temp_crit.name,
189				sizeof(temp->temp_crit.name),
190				"temp%d_crit", hwmon->count);
191		temp->temp_crit.attr.attr.name = temp->temp_crit.name;
192		temp->temp_crit.attr.attr.mode = 0444;
193		temp->temp_crit.attr.show = temp_crit_show;
194		sysfs_attr_init(&temp->temp_crit.attr.attr);
195		result = device_create_file(hwmon->device,
196					    &temp->temp_crit.attr);
197		if (result)
198			goto unregister_input;
199	}
200
201	mutex_lock(&thermal_hwmon_list_lock);
202	if (new_hwmon_device)
203		list_add_tail(&hwmon->node, &thermal_hwmon_list);
204	list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
205	mutex_unlock(&thermal_hwmon_list_lock);
206
207	return 0;
208
209 unregister_input:
210	device_remove_file(hwmon->device, &temp->temp_input.attr);
211 free_temp_mem:
212	kfree(temp);
213 unregister_name:
214	if (new_hwmon_device)
215		hwmon_device_unregister(hwmon->device);
216 free_mem:
217	if (new_hwmon_device)
218		kfree(hwmon);
219
220	return result;
221}
222EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
223
224void 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}
260EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);