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-rw-r--r-- | Documentation/thermal/sysfs-api.txt | 380 |
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 @@ | |||
1 | Generic Thermal Sysfs driver How To | 1 | Generic Thermal Sysfs driver How To |
2 | ========================= | 2 | =================================== |
3 | 3 | ||
4 | Written by Sujith Thomas <sujith.thomas@intel.com>, Zhang Rui <rui.zhang@intel.com> | 4 | Written 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 | ||
11 | 0. Introduction | 11 | 0. Introduction |
12 | 12 | ||
13 | The generic thermal sysfs provides a set of interfaces for thermal zone devices (sensors) | 13 | The generic thermal sysfs provides a set of interfaces for thermal zone |
14 | and thermal cooling devices (fan, processor...) to register with the thermal management | 14 | devices (sensors) and thermal cooling devices (fan, processor...) to register |
15 | solution and to be a part of it. | 15 | with the thermal management solution and to be a part of it. |
16 | 16 | ||
17 | This how-to focuses on enabling new thermal zone and cooling devices to participate | 17 | This how-to focuses on enabling new thermal zone and cooling devices to |
18 | in thermal management. | 18 | participate in thermal management. |
19 | This solution is platform independent and any type of thermal zone devices and | 19 | This solution is platform independent and any type of thermal zone devices |
20 | cooling devices should be able to make use of the infrastructure. | 20 | and cooling devices should be able to make use of the infrastructure. |
21 | 21 | ||
22 | The main task of the thermal sysfs driver is to expose thermal zone attributes as well | 22 | The main task of the thermal sysfs driver is to expose thermal zone attributes |
23 | as cooling device attributes to the user space. | 23 | as well as cooling device attributes to the user space. |
24 | An intelligent thermal management application can make decisions based on inputs | 24 | An intelligent thermal management application can make decisions based on |
25 | from thermal zone attributes (the current temperature and trip point temperature) | 25 | inputs from thermal zone attributes (the current temperature and trip point |
26 | and throttle appropriate devices. | 26 | temperature) 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. | |||
31 | 1. thermal sysfs driver interface functions | 31 | 1. thermal sysfs driver interface functions |
32 | 32 | ||
33 | 1.1 thermal zone device interface | 33 | 1.1 thermal zone device interface |
34 | 1.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name, int trips, | 34 | 1.1.1 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 | ||
57 | 1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz) | 57 | 1.1.2 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 | ||
63 | 1.2 thermal cooling device interface | 63 | 1.2 thermal cooling device interface |
64 | 1.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char *name, | 64 | 1.2.1 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 | ||
77 | 1.2.2 void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev) | 77 | 1.2.2 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 | ||
83 | 1.3 interface for binding a thermal zone device with a thermal cooling device | 83 | 1.3 interface for binding a thermal zone device with a thermal cooling device |
84 | 1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz, | 84 | 1.3.1 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 | ||
95 | 1.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz, | 95 | 1.3.2 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 | ||
106 | 2. sysfs attributes structure | 106 | 2. sysfs attributes structure |
107 | 107 | ||
@@ -114,153 +114,157 @@ if hwmon is compiled in or built as a module. | |||
114 | 114 | ||
115 | Thermal zone device sys I/F, created once it's registered: | 115 | Thermal 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 | ||
123 | Thermal cooling device sys I/F, created once it's registered: | 123 | Thermal 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 | ||
130 | These two dynamic attributes are created/removed in pairs. | 130 | Then next two dynamic attributes are created/removed in pairs. They represent |
131 | They represent the relationship between a thermal zone and its associated cooling device. | 131 | the relationship between a thermal zone and its associated cooling device. |
132 | They are created/removed for each | 132 | They are created/removed for each successful execution of |
133 | thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device successful execution. | 133 | thermal_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 | ||
139 | Besides the thermal zone device sysfs I/F and cooling device sysfs I/F, | 139 | Besides the thermal zone device sysfs I/F and cooling device sysfs I/F, |
140 | the generic thermal driver also creates a hwmon sysfs I/F for each _type_ of | 140 | the generic thermal driver also creates a hwmon sysfs I/F for each _type_ |
141 | thermal zone device. E.g. the generic thermal driver registers one hwmon class device | 141 | of thermal zone device. E.g. the generic thermal driver registers one hwmon |
142 | and build the associated hwmon sysfs I/F for all the registered ACPI thermal zones. | 142 | class device and build the associated hwmon sysfs I/F for all the registered |
143 | ACPI 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 | |||
147 | Please read Documentation/hwmon/sysfs-interface for additional information. | 150 | Please read Documentation/hwmon/sysfs-interface for additional information. |
148 | 151 | ||
149 | *************************** | 152 | *************************** |
150 | * Thermal zone attributes * | 153 | * Thermal zone attributes * |
151 | *************************** | 154 | *************************** |
152 | 155 | ||
153 | type Strings which represent the thermal zone type. | 156 | type |
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 | 164 | temp | |
162 | temp 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 | 169 | mode | |
167 | mode 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. | 180 | trip_point_[0-*]_temp |
178 | 181 | The temperature above which trip point will be fired. | |
179 | trip_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 | 185 | trip_point_[0-*]_type |
183 | 186 | Strings which indicate the type of the trip point. | |
184 | trip_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 | 191 | cdev[0-*] |
189 | 192 | Sysfs link to the thermal cooling device node where the sys I/F | |
190 | cdev[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 | 196 | cdev[0-*]_trip_point |
194 | 197 | The trip point with which cdev[0-*] is associated in this thermal | |
195 | cdev[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 | 206 | type | |
204 | type 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 | 213 | max_state |
211 | 214 | The maximum permissible cooling state of this cooling device. | |
212 | max_state The maximum permissible cooling state of this cooling device. | 215 | RO, Required |
213 | RO | 216 | |
214 | Required | 217 | cur_state |
215 | 218 | The current cooling state of this cooling device. | |
216 | cur_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 | ||
223 | 3. A simple implementation | 224 | 3. A simple implementation |
224 | 225 | ||
225 | ACPI thermal zone may support multiple trip points like critical/hot/passive/active. | 226 | ACPI thermal zone may support multiple trip points like critical, hot, |
226 | If an ACPI thermal zone supports critical, passive, active[0] and active[1] at the same time, | 227 | passive, active. If an ACPI thermal zone supports critical, passive, |
227 | it may register itself as a thermal_zone_device (thermal_zone1) with 4 trip points in all. | 228 | active[0] and active[1] at the same time, it may register itself as a |
228 | It has one processor and one fan, which are both registered as thermal_cooling_device. | 229 | thermal_zone_device (thermal_zone1) with 4 trip points in all. |
229 | If the processor is listed in _PSL method, and the fan is listed in _AL0 method, | 230 | It has one processor and one fan, which are both registered as |
230 | the sys I/F structure will be built like this: | 231 | thermal_cooling_device. |
232 | |||
233 | If the processor is listed in _PSL method, and the fan is listed in _AL0 | ||
234 | method, 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 |