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Diffstat (limited to 'Documentation/thermal/sysfs-api.txt')
| -rw-r--r-- | Documentation/thermal/sysfs-api.txt | 103 |
1 files changed, 91 insertions, 12 deletions
diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt index 1733ab947a95..88c02334e356 100644 --- a/Documentation/thermal/sysfs-api.txt +++ b/Documentation/thermal/sysfs-api.txt @@ -32,7 +32,8 @@ temperature) and throttle appropriate devices. 1.1 thermal zone device interface 1.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name, - int trips, void *devdata, struct thermal_zone_device_ops *ops) + int trips, int mask, void *devdata, + struct thermal_zone_device_ops *ops) This interface function adds a new thermal zone device (sensor) to /sys/class/thermal folder as thermal_zone[0-*]. It tries to bind all the @@ -40,16 +41,17 @@ temperature) and throttle appropriate devices. name: the thermal zone name. trips: the total number of trip points this thermal zone supports. + mask: Bit string: If 'n'th bit is set, then trip point 'n' is writeable. devdata: device private data ops: thermal zone device call-backs. .bind: bind the thermal zone device with a thermal cooling device. .unbind: unbind the thermal zone device with a thermal cooling device. .get_temp: get the current temperature of the thermal zone. - .get_mode: get the current mode (user/kernel) of the thermal zone. - - "kernel" means thermal management is done in kernel. - - "user" will prevent kernel thermal driver actions upon trip points + .get_mode: get the current mode (enabled/disabled) of the thermal zone. + - "enabled" means the kernel thermal management is enabled. + - "disabled" will prevent kernel thermal driver action upon trip points so that user applications can take charge of thermal management. - .set_mode: set the mode (user/kernel) of the thermal zone. + .set_mode: set the mode (enabled/disabled) of the thermal zone. .get_trip_type: get the type of certain trip point. .get_trip_temp: get the temperature above which the certain trip point will be fired. @@ -82,7 +84,8 @@ temperature) and throttle appropriate devices. 1.3 interface for binding a thermal zone device with a thermal cooling device 1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz, - int trip, struct thermal_cooling_device *cdev); + int trip, struct thermal_cooling_device *cdev, + unsigned long upper, unsigned long lower); This interface function bind a thermal cooling device to the certain trip point of a thermal zone device. @@ -91,6 +94,12 @@ temperature) and throttle appropriate devices. cdev: thermal cooling device trip: indicates which trip point the cooling devices is associated with in this thermal zone. + upper:the Maximum cooling state for this trip point. + THERMAL_NO_LIMIT means no upper limit, + and the cooling device can be in max_state. + lower:the Minimum cooling state can be used for this trip point. + THERMAL_NO_LIMIT means no lower limit, + and the cooling device can be in cooling state 0. 1.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz, int trip, struct thermal_cooling_device *cdev); @@ -103,6 +112,29 @@ temperature) and throttle appropriate devices. trip: indicates which trip point the cooling devices is associated with in this thermal zone. +1.4 Thermal Zone Parameters +1.4.1 struct thermal_bind_params + This structure defines the following parameters that are used to bind + a zone with a cooling device for a particular trip point. + .cdev: The cooling device pointer + .weight: The 'influence' of a particular cooling device on this zone. + This is on a percentage scale. The sum of all these weights + (for a particular zone) cannot exceed 100. + .trip_mask:This is a bit mask that gives the binding relation between + this thermal zone and cdev, for a particular trip point. + If nth bit is set, then the cdev and thermal zone are bound + for trip point n. + .match: This call back returns success(0) if the 'tz and cdev' need to + be bound, as per platform data. +1.4.2 struct thermal_zone_params + This structure defines the platform level parameters for a thermal zone. + This data, for each thermal zone should come from the platform layer. + This is an optional feature where some platforms can choose not to + provide this data. + .governor_name: Name of the thermal governor used for this zone + .num_tbps: Number of thermal_bind_params entries for this zone + .tbp: thermal_bind_params entries + 2. sysfs attributes structure RO read only value @@ -117,8 +149,10 @@ Thermal zone device sys I/F, created once it's registered: |---type: Type of the thermal zone |---temp: Current temperature |---mode: Working mode of the thermal zone + |---policy: Thermal governor used for this zone |---trip_point_[0-*]_temp: Trip point temperature |---trip_point_[0-*]_type: Trip point type + |---trip_point_[0-*]_hyst: Hysteresis value for this trip point Thermal cooling device sys I/F, created once it's registered: /sys/class/thermal/cooling_device[0-*]: @@ -167,16 +201,20 @@ temp RO, Required mode - One of the predefined values in [kernel, user]. + One of the predefined values in [enabled, disabled]. This file gives information about the algorithm that is currently managing the thermal zone. It can be either default kernel based algorithm or user space application. - kernel = Thermal management in kernel thermal zone driver. - user = Preventing kernel thermal zone driver actions upon - trip points so that user application can take full - charge of the thermal management. + enabled = enable Kernel Thermal management. + disabled = Preventing kernel thermal zone driver actions upon + trip points so that user application can take full + charge of the thermal management. RW, Optional +policy + One of the various thermal governors used for a particular zone. + RW, Required + trip_point_[0-*]_temp The temperature above which trip point will be fired. Unit: millidegree Celsius @@ -188,6 +226,11 @@ trip_point_[0-*]_type thermal zone. RO, Optional +trip_point_[0-*]_hyst + The hysteresis value for a trip point, represented as an integer + Unit: Celsius + RW, Optional + cdev[0-*] Sysfs link to the thermal cooling device node where the sys I/F for cooling device throttling control represents. @@ -248,7 +291,8 @@ method, the sys I/F structure will be built like this: |thermal_zone1: |---type: acpitz |---temp: 37000 - |---mode: kernel + |---mode: enabled + |---policy: step_wise |---trip_point_0_temp: 100000 |---trip_point_0_type: critical |---trip_point_1_temp: 80000 @@ -290,3 +334,38 @@ to a thermal_zone_device when it registers itself with the framework. The event will be one of:{THERMAL_AUX0, THERMAL_AUX1, THERMAL_CRITICAL, THERMAL_DEV_FAULT}. Notification can be sent when the current temperature crosses any of the configured thresholds. + +5. Export Symbol APIs: + +5.1: get_tz_trend: +This function returns the trend of a thermal zone, i.e the rate of change +of temperature of the thermal zone. Ideally, the thermal sensor drivers +are supposed to implement the callback. If they don't, the thermal +framework calculated the trend by comparing the previous and the current +temperature values. + +5.2:get_thermal_instance: +This function returns the thermal_instance corresponding to a given +{thermal_zone, cooling_device, trip_point} combination. Returns NULL +if such an instance does not exist. + +5.3:notify_thermal_framework: +This function handles the trip events from sensor drivers. It starts +throttling the cooling devices according to the policy configured. +For CRITICAL and HOT trip points, this notifies the respective drivers, +and does actual throttling for other trip points i.e ACTIVE and PASSIVE. +The throttling policy is based on the configured platform data; if no +platform data is provided, this uses the step_wise throttling policy. + +5.4:thermal_cdev_update: +This function serves as an arbitrator to set the state of a cooling +device. It sets the cooling device to the deepest cooling state if +possible. + +5.5:thermal_register_governor: +This function lets the various thermal governors to register themselves +with the Thermal framework. At run time, depending on a zone's platform +data, a particular governor is used for throttling. + +5.6:thermal_unregister_governor: +This function unregisters a governor from the thermal framework. |