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authorFrans Pop <elendil@planet.nl>2009-10-26 03:38:59 -0400
committerLen Brown <len.brown@intel.com>2009-11-05 18:06:05 -0500
commit38bb0849a6799e05bb474a88f198522ae4ecace2 (patch)
treebb7140ec98bfe7bc1d0b5fa5836dab73a9f11cc7 /Documentation
parent625120a42bd4371da98808a4ca3e7589083a06d8 (diff)
thermal: sysfs-api.txt - reformat for improved readability
The document currently uses large indentations which make the text too wide for easy readability. Also improve general consistency. Signed-off-by: Frans Pop <elendil@planet.nl> Acked-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/thermal/sysfs-api.txt380
1 files changed, 192 insertions, 188 deletions
diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
index 70d68ce8640a..895337f8c6ba 100644
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -1,5 +1,5 @@
1Generic Thermal Sysfs driver How To 1Generic Thermal Sysfs driver How To
2========================= 2===================================
3 3
4Written by Sujith Thomas <sujith.thomas@intel.com>, Zhang Rui <rui.zhang@intel.com> 4Written by Sujith Thomas <sujith.thomas@intel.com>, Zhang Rui <rui.zhang@intel.com>
5 5
@@ -10,20 +10,20 @@ Copyright (c) 2008 Intel Corporation
10 10
110. Introduction 110. Introduction
12 12
13The generic thermal sysfs provides a set of interfaces for thermal zone devices (sensors) 13The generic thermal sysfs provides a set of interfaces for thermal zone
14and thermal cooling devices (fan, processor...) to register with the thermal management 14devices (sensors) and thermal cooling devices (fan, processor...) to register
15solution and to be a part of it. 15with the thermal management solution and to be a part of it.
16 16
17This how-to focuses on enabling new thermal zone and cooling devices to participate 17This how-to focuses on enabling new thermal zone and cooling devices to
18in thermal management. 18participate in thermal management.
19This solution is platform independent and any type of thermal zone devices and 19This solution is platform independent and any type of thermal zone devices
20cooling devices should be able to make use of the infrastructure. 20and cooling devices should be able to make use of the infrastructure.
21 21
22The main task of the thermal sysfs driver is to expose thermal zone attributes as well 22The main task of the thermal sysfs driver is to expose thermal zone attributes
23as cooling device attributes to the user space. 23as well as cooling device attributes to the user space.
24An intelligent thermal management application can make decisions based on inputs 24An intelligent thermal management application can make decisions based on
25from thermal zone attributes (the current temperature and trip point temperature) 25inputs from thermal zone attributes (the current temperature and trip point
26and throttle appropriate devices. 26temperature) and throttle appropriate devices.
27 27
28[0-*] denotes any positive number starting from 0 28[0-*] denotes any positive number starting from 0
29[1-*] denotes any positive number starting from 1 29[1-*] denotes any positive number starting from 1
@@ -31,77 +31,77 @@ and throttle appropriate devices.
311. thermal sysfs driver interface functions 311. thermal sysfs driver interface functions
32 32
331.1 thermal zone device interface 331.1 thermal zone device interface
341.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name, int trips, 341.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name,
35 void *devdata, struct thermal_zone_device_ops *ops) 35 int trips, void *devdata, struct thermal_zone_device_ops *ops)
36 36
37 This interface function adds a new thermal zone device (sensor) to 37 This interface function adds a new thermal zone device (sensor) to
38 /sys/class/thermal folder as thermal_zone[0-*]. 38 /sys/class/thermal folder as thermal_zone[0-*]. It tries to bind all the
39 It tries to bind all the thermal cooling devices registered at the same time. 39 thermal cooling devices registered at the same time.
40 40
41 name: the thermal zone name. 41 name: the thermal zone name.
42 trips: the total number of trip points this thermal zone supports. 42 trips: the total number of trip points this thermal zone supports.
43 devdata: device private data 43 devdata: device private data
44 ops: thermal zone device call-backs. 44 ops: thermal zone device call-backs.
45 .bind: bind the thermal zone device with a thermal cooling device. 45 .bind: bind the thermal zone device with a thermal cooling device.
46 .unbind: unbind the thermal zone device with a thermal cooling device. 46 .unbind: unbind the thermal zone device with a thermal cooling device.
47 .get_temp: get the current temperature of the thermal zone. 47 .get_temp: get the current temperature of the thermal zone.
48 .get_mode: get the current mode (user/kernel) of the thermal zone. 48 .get_mode: get the current mode (user/kernel) of the thermal zone.
49 "kernel" means thermal management is done in kernel. 49 - "kernel" means thermal management is done in kernel.
50 "user" will prevent kernel thermal driver actions upon trip points 50 - "user" will prevent kernel thermal driver actions upon trip points
51 so that user applications can take charge of thermal management. 51 so that user applications can take charge of thermal management.
52 .set_mode: set the mode (user/kernel) of the thermal zone. 52 .set_mode: set the mode (user/kernel) of the thermal zone.
53 .get_trip_type: get the type of certain trip point. 53 .get_trip_type: get the type of certain trip point.
54 .get_trip_temp: get the temperature above which the certain trip point 54 .get_trip_temp: get the temperature above which the certain trip point
55 will be fired. 55 will be fired.
56 56
571.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz) 571.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz)
58 58
59 This interface function removes the thermal zone device. 59 This interface function removes the thermal zone device.
60 It deletes the corresponding entry form /sys/class/thermal folder and unbind all 60 It deletes the corresponding entry form /sys/class/thermal folder and
61 the thermal cooling devices it uses. 61 unbind all the thermal cooling devices it uses.
62 62
631.2 thermal cooling device interface 631.2 thermal cooling device interface
641.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char *name, 641.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char *name,
65 void *devdata, struct thermal_cooling_device_ops *) 65 void *devdata, struct thermal_cooling_device_ops *)
66 66
67 This interface function adds a new thermal cooling device (fan/processor/...) to 67 This interface function adds a new thermal cooling device (fan/processor/...)
68 /sys/class/thermal/ folder as cooling_device[0-*]. 68 to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself
69 It tries to bind itself to all the thermal zone devices register at the same time. 69 to all the thermal zone devices register at the same time.
70 name: the cooling device name. 70 name: the cooling device name.
71 devdata: device private data. 71 devdata: device private data.
72 ops: thermal cooling devices call-backs. 72 ops: thermal cooling devices call-backs.
73 .get_max_state: get the Maximum throttle state of the cooling device. 73 .get_max_state: get the Maximum throttle state of the cooling device.
74 .get_cur_state: get the Current throttle state of the cooling device. 74 .get_cur_state: get the Current throttle state of the cooling device.
75 .set_cur_state: set the Current throttle state of the cooling device. 75 .set_cur_state: set the Current throttle state of the cooling device.
76 76
771.2.2 void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev) 771.2.2 void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
78 78
79 This interface function remove the thermal cooling device. 79 This interface function remove the thermal cooling device.
80 It deletes the corresponding entry form /sys/class/thermal folder and unbind 80 It deletes the corresponding entry form /sys/class/thermal folder and
81 itself from all the thermal zone devices using it. 81 unbind itself from all the thermal zone devices using it.
82 82
831.3 interface for binding a thermal zone device with a thermal cooling device 831.3 interface for binding a thermal zone device with a thermal cooling device
841.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz, 841.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
85 int trip, struct thermal_cooling_device *cdev); 85 int trip, struct thermal_cooling_device *cdev);
86 86
87 This interface function bind a thermal cooling device to the certain trip point 87 This interface function bind a thermal cooling device to the certain trip
88 of a thermal zone device. 88 point of a thermal zone device.
89 This function is usually called in the thermal zone device .bind callback. 89 This function is usually called in the thermal zone device .bind callback.
90 tz: the thermal zone device 90 tz: the thermal zone device
91 cdev: thermal cooling device 91 cdev: thermal cooling device
92 trip: indicates which trip point the cooling devices is associated with 92 trip: indicates which trip point the cooling devices is associated with
93 in this thermal zone. 93 in this thermal zone.
94 94
951.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz, 951.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,
96 int trip, struct thermal_cooling_device *cdev); 96 int trip, struct thermal_cooling_device *cdev);
97 97
98 This interface function unbind a thermal cooling device from the certain trip point 98 This interface function unbind a thermal cooling device from the certain
99 of a thermal zone device. 99 trip point of a thermal zone device. This function is usually called in
100 This function is usually called in the thermal zone device .unbind callback. 100 the thermal zone device .unbind callback.
101 tz: the thermal zone device 101 tz: the thermal zone device
102 cdev: thermal cooling device 102 cdev: thermal cooling device
103 trip: indicates which trip point the cooling devices is associated with 103 trip: indicates which trip point the cooling devices is associated with
104 in this thermal zone. 104 in this thermal zone.
105 105
1062. sysfs attributes structure 1062. sysfs attributes structure
107 107
@@ -114,153 +114,157 @@ if hwmon is compiled in or built as a module.
114 114
115Thermal zone device sys I/F, created once it's registered: 115Thermal zone device sys I/F, created once it's registered:
116/sys/class/thermal/thermal_zone[0-*]: 116/sys/class/thermal/thermal_zone[0-*]:
117 |-----type: Type of the thermal zone 117 |---type: Type of the thermal zone
118 |-----temp: Current temperature 118 |---temp: Current temperature
119 |-----mode: Working mode of the thermal zone 119 |---mode: Working mode of the thermal zone
120 |-----trip_point_[0-*]_temp: Trip point temperature 120 |---trip_point_[0-*]_temp: Trip point temperature
121 |-----trip_point_[0-*]_type: Trip point type 121 |---trip_point_[0-*]_type: Trip point type
122 122
123Thermal cooling device sys I/F, created once it's registered: 123Thermal cooling device sys I/F, created once it's registered:
124/sys/class/thermal/cooling_device[0-*]: 124/sys/class/thermal/cooling_device[0-*]:
125 |-----type : Type of the cooling device(processor/fan/...) 125 |---type: Type of the cooling device(processor/fan/...)
126 |-----max_state: Maximum cooling state of the cooling device 126 |---max_state: Maximum cooling state of the cooling device
127 |-----cur_state: Current cooling state of the cooling device 127 |---cur_state: Current cooling state of the cooling device
128 128
129 129
130These two dynamic attributes are created/removed in pairs. 130Then next two dynamic attributes are created/removed in pairs. They represent
131They represent the relationship between a thermal zone and its associated cooling device. 131the relationship between a thermal zone and its associated cooling device.
132They are created/removed for each 132They are created/removed for each successful execution of
133thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device successful execution. 133thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device.
134 134
135/sys/class/thermal/thermal_zone[0-*] 135/sys/class/thermal/thermal_zone[0-*]:
136 |-----cdev[0-*]: The [0-*]th cooling device in the current thermal zone 136 |---cdev[0-*]: [0-*]th cooling device in current thermal zone
137 |-----cdev[0-*]_trip_point: Trip point that cdev[0-*] is associated with 137 |---cdev[0-*]_trip_point: Trip point that cdev[0-*] is associated with
138 138
139Besides the thermal zone device sysfs I/F and cooling device sysfs I/F, 139Besides the thermal zone device sysfs I/F and cooling device sysfs I/F,
140the generic thermal driver also creates a hwmon sysfs I/F for each _type_ of 140the generic thermal driver also creates a hwmon sysfs I/F for each _type_
141thermal zone device. E.g. the generic thermal driver registers one hwmon class device 141of thermal zone device. E.g. the generic thermal driver registers one hwmon
142and build the associated hwmon sysfs I/F for all the registered ACPI thermal zones. 142class device and build the associated hwmon sysfs I/F for all the registered
143ACPI thermal zones.
144
143/sys/class/hwmon/hwmon[0-*]: 145/sys/class/hwmon/hwmon[0-*]:
144 |-----name: The type of the thermal zone devices. 146 |---name: The type of the thermal zone devices
145 |-----temp[1-*]_input: The current temperature of thermal zone [1-*]. 147 |---temp[1-*]_input: The current temperature of thermal zone [1-*]
146 |-----temp[1-*]_critical: The critical trip point of thermal zone [1-*]. 148 |---temp[1-*]_critical: The critical trip point of thermal zone [1-*]
149
147Please read Documentation/hwmon/sysfs-interface for additional information. 150Please read Documentation/hwmon/sysfs-interface for additional information.
148 151
149*************************** 152***************************
150* Thermal zone attributes * 153* Thermal zone attributes *
151*************************** 154***************************
152 155
153type Strings which represent the thermal zone type. 156type
154 This is given by thermal zone driver as part of registration. 157 Strings which represent the thermal zone type.
155 Eg: "acpitz" indicates it's an ACPI thermal device. 158 This is given by thermal zone driver as part of registration.
156 In order to keep it consistent with hwmon sys attribute, 159 E.g: "acpitz" indicates it's an ACPI thermal device.
157 this should be a short, lowercase string, 160 In order to keep it consistent with hwmon sys attribute; this should
158 not containing spaces nor dashes. 161 be a short, lowercase string, not containing spaces nor dashes.
159 RO 162 RO, Required
160 Required 163
161 164temp
162temp Current temperature as reported by thermal zone (sensor) 165 Current temperature as reported by thermal zone (sensor).
163 Unit: millidegree Celsius 166 Unit: millidegree Celsius
164 RO 167 RO, Required
165 Required 168
166 169mode
167mode One of the predefined values in [kernel, user] 170 One of the predefined values in [kernel, user].
168 This file gives information about the algorithm 171 This file gives information about the algorithm that is currently
169 that is currently managing the thermal zone. 172 managing the thermal zone. It can be either default kernel based
170 It can be either default kernel based algorithm 173 algorithm or user space application.
171 or user space application. 174 kernel = Thermal management in kernel thermal zone driver.
172 RW 175 user = Preventing kernel thermal zone driver actions upon
173 Optional 176 trip points so that user application can take full
174 kernel = Thermal management in kernel thermal zone driver. 177 charge of the thermal management.
175 user = Preventing kernel thermal zone driver actions upon 178 RW, Optional
176 trip points so that user application can take full 179
177 charge of the thermal management. 180trip_point_[0-*]_temp
178 181 The temperature above which trip point will be fired.
179trip_point_[0-*]_temp The temperature above which trip point will be fired 182 Unit: millidegree Celsius
180 Unit: millidegree Celsius 183 RO, Optional
181 RO 184
182 Optional 185trip_point_[0-*]_type
183 186 Strings which indicate the type of the trip point.
184trip_point_[0-*]_type Strings which indicate the type of the trip point 187 E.g. it can be one of critical, hot, passive, active[0-*] for ACPI
185 E.g. it can be one of critical, hot, passive, 188 thermal zone.
186 active[0-*] for ACPI thermal zone. 189 RO, Optional
187 RO 190
188 Optional 191cdev[0-*]
189 192 Sysfs link to the thermal cooling device node where the sys I/F
190cdev[0-*] Sysfs link to the thermal cooling device node where the sys I/F 193 for cooling device throttling control represents.
191 for cooling device throttling control represents. 194 RO, Optional
192 RO 195
193 Optional 196cdev[0-*]_trip_point
194 197 The trip point with which cdev[0-*] is associated in this thermal
195cdev[0-*]_trip_point The trip point with which cdev[0-*] is associated in this thermal zone 198 zone; -1 means the cooling device is not associated with any trip
196 -1 means the cooling device is not associated with any trip point. 199 point.
197 RO 200 RO, Optional
198 Optional 201
199 202*****************************
200****************************** 203* Cooling device attributes *
201* Cooling device attributes * 204*****************************
202****************************** 205
203 206type
204type String which represents the type of device 207 String which represents the type of device, e.g:
205 eg: For generic ACPI: this should be "Fan", 208 - for generic ACPI: should be "Fan", "Processor" or "LCD"
206 "Processor" or "LCD" 209 - for memory controller device on intel_menlow platform:
207 eg. For memory controller device on intel_menlow platform: 210 should be "Memory controller".
208 this should be "Memory controller" 211 RO, Required
209 RO 212
210 Required 213max_state
211 214 The maximum permissible cooling state of this cooling device.
212max_state The maximum permissible cooling state of this cooling device. 215 RO, Required
213 RO 216
214 Required 217cur_state
215 218 The current cooling state of this cooling device.
216cur_state The current cooling state of this cooling device. 219 The value can any integer numbers between 0 and max_state:
217 the value can any integer numbers between 0 and max_state, 220 - cur_state == 0 means no cooling
218 cur_state == 0 means no cooling 221 - cur_state == max_state means the maximum cooling.
219 cur_state == max_state means the maximum cooling. 222 RW, Required
220 RW
221 Required
222 223
2233. A simple implementation 2243. A simple implementation
224 225
225ACPI thermal zone may support multiple trip points like critical/hot/passive/active. 226ACPI thermal zone may support multiple trip points like critical, hot,
226If an ACPI thermal zone supports critical, passive, active[0] and active[1] at the same time, 227passive, active. If an ACPI thermal zone supports critical, passive,
227it may register itself as a thermal_zone_device (thermal_zone1) with 4 trip points in all. 228active[0] and active[1] at the same time, it may register itself as a
228It has one processor and one fan, which are both registered as thermal_cooling_device. 229thermal_zone_device (thermal_zone1) with 4 trip points in all.
229If the processor is listed in _PSL method, and the fan is listed in _AL0 method, 230It has one processor and one fan, which are both registered as
230the sys I/F structure will be built like this: 231thermal_cooling_device.
232
233If the processor is listed in _PSL method, and the fan is listed in _AL0
234method, the sys I/F structure will be built like this:
231 235
232/sys/class/thermal: 236/sys/class/thermal:
233 237
234|thermal_zone1: 238|thermal_zone1:
235 |-----type: acpitz 239 |---type: acpitz
236 |-----temp: 37000 240 |---temp: 37000
237 |-----mode: kernel 241 |---mode: kernel
238 |-----trip_point_0_temp: 100000 242 |---trip_point_0_temp: 100000
239 |-----trip_point_0_type: critical 243 |---trip_point_0_type: critical
240 |-----trip_point_1_temp: 80000 244 |---trip_point_1_temp: 80000
241 |-----trip_point_1_type: passive 245 |---trip_point_1_type: passive
242 |-----trip_point_2_temp: 70000 246 |---trip_point_2_temp: 70000
243 |-----trip_point_2_type: active0 247 |---trip_point_2_type: active0
244 |-----trip_point_3_temp: 60000 248 |---trip_point_3_temp: 60000
245 |-----trip_point_3_type: active1 249 |---trip_point_3_type: active1
246 |-----cdev0: --->/sys/class/thermal/cooling_device0 250 |---cdev0: --->/sys/class/thermal/cooling_device0
247 |-----cdev0_trip_point: 1 /* cdev0 can be used for passive */ 251 |---cdev0_trip_point: 1 /* cdev0 can be used for passive */
248 |-----cdev1: --->/sys/class/thermal/cooling_device3 252 |---cdev1: --->/sys/class/thermal/cooling_device3
249 |-----cdev1_trip_point: 2 /* cdev1 can be used for active[0]*/ 253 |---cdev1_trip_point: 2 /* cdev1 can be used for active[0]*/
250 254
251|cooling_device0: 255|cooling_device0:
252 |-----type: Processor 256 |---type: Processor
253 |-----max_state: 8 257 |---max_state: 8
254 |-----cur_state: 0 258 |---cur_state: 0
255 259
256|cooling_device3: 260|cooling_device3:
257 |-----type: Fan 261 |---type: Fan
258 |-----max_state: 2 262 |---max_state: 2
259 |-----cur_state: 0 263 |---cur_state: 0
260 264
261/sys/class/hwmon: 265/sys/class/hwmon:
262 266
263|hwmon0: 267|hwmon0:
264 |-----name: acpitz 268 |---name: acpitz
265 |-----temp1_input: 37000 269 |---temp1_input: 37000
266 |-----temp1_crit: 100000 270 |---temp1_crit: 100000