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	long 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, "%ld\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	long 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, "%ld\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
143int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
144{
145	struct thermal_hwmon_device *hwmon;
146	struct thermal_hwmon_temp *temp;
147	int new_hwmon_device = 1;
148	int result;
149
150	hwmon = thermal_hwmon_lookup_by_type(tz);
151	if (hwmon) {
152		new_hwmon_device = 0;
153		goto register_sys_interface;
154	}
155
156	hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
157	if (!hwmon)
158		return -ENOMEM;
159
160	INIT_LIST_HEAD(&hwmon->tz_list);
161	strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
162	hwmon->device = hwmon_device_register(NULL);
163	if (IS_ERR(hwmon->device)) {
164		result = PTR_ERR(hwmon->device);
165		goto free_mem;
166	}
167	dev_set_drvdata(hwmon->device, hwmon);
168	result = device_create_file(hwmon->device, &dev_attr_name);
169	if (result)
170		goto free_mem;
171
172 register_sys_interface:
173	temp = kzalloc(sizeof(*temp), GFP_KERNEL);
174	if (!temp) {
175		result = -ENOMEM;
176		goto unregister_name;
177	}
178
179	temp->tz = tz;
180	hwmon->count++;
181
182	snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
183		 "temp%d_input", hwmon->count);
184	temp->temp_input.attr.attr.name = temp->temp_input.name;
185	temp->temp_input.attr.attr.mode = 0444;
186	temp->temp_input.attr.show = temp_input_show;
187	sysfs_attr_init(&temp->temp_input.attr.attr);
188	result = device_create_file(hwmon->device, &temp->temp_input.attr);
189	if (result)
190		goto free_temp_mem;
191
192	if (tz->ops->get_crit_temp) {
193		unsigned long temperature;
194		if (!tz->ops->get_crit_temp(tz, &temperature)) {
195			snprintf(temp->temp_crit.name,
196				 sizeof(temp->temp_crit.name),
197				"temp%d_crit", hwmon->count);
198			temp->temp_crit.attr.attr.name = temp->temp_crit.name;
199			temp->temp_crit.attr.attr.mode = 0444;
200			temp->temp_crit.attr.show = temp_crit_show;
201			sysfs_attr_init(&temp->temp_crit.attr.attr);
202			result = device_create_file(hwmon->device,
203						    &temp->temp_crit.attr);
204			if (result)
205				goto unregister_input;
206		}
207	}
208
209	mutex_lock(&thermal_hwmon_list_lock);
210	if (new_hwmon_device)
211		list_add_tail(&hwmon->node, &thermal_hwmon_list);
212	list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
213	mutex_unlock(&thermal_hwmon_list_lock);
214
215	return 0;
216
217 unregister_input:
218	device_remove_file(hwmon->device, &temp->temp_input.attr);
219 free_temp_mem:
220	kfree(temp);
221 unregister_name:
222	if (new_hwmon_device) {
223		device_remove_file(hwmon->device, &dev_attr_name);
224		hwmon_device_unregister(hwmon->device);
225	}
226 free_mem:
227	if (new_hwmon_device)
228		kfree(hwmon);
229
230	return result;
231}
232
233void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
234{
235	struct thermal_hwmon_device *hwmon;
236	struct thermal_hwmon_temp *temp;
237
238	hwmon = thermal_hwmon_lookup_by_type(tz);
239	if (unlikely(!hwmon)) {
240		/* Should never happen... */
241		dev_dbg(&tz->device, "hwmon device lookup failed!\n");
242		return;
243	}
244
245	temp = thermal_hwmon_lookup_temp(hwmon, tz);
246	if (unlikely(!temp)) {
247		/* Should never happen... */
248		dev_dbg(&tz->device, "temperature input lookup failed!\n");
249		return;
250	}
251
252	device_remove_file(hwmon->device, &temp->temp_input.attr);
253	if (tz->ops->get_crit_temp)
254		device_remove_file(hwmon->device, &temp->temp_crit.attr);
255
256	mutex_lock(&thermal_hwmon_list_lock);
257	list_del(&temp->hwmon_node);
258	kfree(temp);
259	if (!list_empty(&hwmon->tz_list)) {
260		mutex_unlock(&thermal_hwmon_list_lock);
261		return;
262	}
263	list_del(&hwmon->node);
264	mutex_unlock(&thermal_hwmon_list_lock);
265
266	device_remove_file(hwmon->device, &dev_attr_name);
267	hwmon_device_unregister(hwmon->device);
268	kfree(hwmon);
269}