Lines Matching refs:OPP
2 Operating Performance Points (OPP) Library
10 2. Initial OPP List Registration
11 3. OPP Search Functions
12 4. OPP Availability Control Functions
13 5. OPP Data Retrieval Functions
19 1.1 What is an Operating Performance Point (OPP)?
48 OPP library provides a set of helper functions to organize and query the OPP
50 is located in include/linux/pm_opp.h. OPP library can be enabled by enabling
51 CONFIG_PM_OPP from power management menuconfig menu. OPP library depends on
53 optionally boot at a certain OPP without needing cpufreq.
55 Typical usage of the OPP library is as follows::
58 SoC framework -> modifies on required cases certain OPPs -> OPP layer
61 OPP layer expects each domain to be represented by a unique device pointer. SoC
62 framework registers a set of initial OPPs per device with the OPP layer. This
67 Note on OPP Availability
73 SoC framework might choose to disable a higher frequency OPP to safely continue
74 operations until that OPP could be re-enabled if possible.
76 OPP library facilitates this concept in it's implementation. The following
83 WARNING: Users of OPP library should refresh their availability count using
87 specific framework which uses the OPP library. Similar care needs to be taken
90 2. Initial OPP List Registration
93 device. It is expected that the SoC framework will register the OPP entries
95 registering the OPPs is maintained by OPP library throughout the device
100 Add a new OPP for a specific domain represented by the device pointer.
101 The OPP is defined using the frequency and voltage. Once added, the OPP
103 with the dev_pm_opp_enable/disable functions. OPP library internally stores
126 3. OPP Search Functions
129 frequency back to the corresponding OPP, OPP library provides handy functions
130 to search the OPP list that OPP library internally manages. These search
136 OPP. Otherwise the memory for the OPP will never get freed and result in
140 Search for an OPP based on an *exact* frequency and
141 availability. This function is especially useful to enable an OPP which
145 find the OPP prior to call the dev_pm_opp_enable to actually make
163 Search for an available OPP which is *at most* the
165 match OR operating on OPP information in the order of decreasing
174 Search for an available OPP which is *at least* the
176 higher match OR operating on OPP information in the order of increasing
199 4. OPP Availability Control Functions
201 A default OPP list registered with the OPP library may not cater to all possible
202 situation. The OPP library provides a set of functions to modify the
203 availability of a OPP within the OPP list. This allows SoC frameworks to have
205 These functions are intended to *temporarily* remove an OPP in conditions such
212 Make a OPP available for operation.
213 Example: Lets say that 1GHz OPP is to be made available only if the
229 Make an OPP to be not available for operation
230 Example: Lets say that 1GHz OPP is to be disabled if the temperature
245 5. OPP Data Retrieval Functions
247 Since OPP library abstracts away the OPP information, a set of functions to pull
248 information from the OPP structure is necessary. Once an OPP pointer is
250 framework to retrieve the information represented inside the OPP layer.
255 framework requires to set the voltage represented by the OPP using
323 domain is represented by a device pointer. The relationship to OPP can be
336 OPP library maintains a internal list that the SoC framework populates and
338 representing the actual OPPs and domains are internal to the OPP library itself
342 The internal data structure of OPP library which is used to
343 represent an OPP. In addition to the freq, voltage, availability
345 for the OPP library to operate on. Pointer to this structure is
347 identifier for OPP in the interactions with OPP layer.
352 dev_pm_opp_add, but the availability of the OPP can be modified
356 This is used to identify a domain to the OPP layer. The
358 OPP library such as the SoC framework.