Home | History | Annotate | Download | only in hardware 
      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_INCLUDE_HARDWARE_POWER_H
     18 #define ANDROID_INCLUDE_HARDWARE_POWER_H
     19 
     20 #include <stdint.h>
     21 #include <sys/cdefs.h>
     22 #include <sys/types.h>
     23 
     24 #include <hardware/hardware.h>
     25 
     26 __BEGIN_DECLS
     27 
     28 #define POWER_MODULE_API_VERSION_0_1  HARDWARE_MODULE_API_VERSION(0, 1)
     29 #define POWER_MODULE_API_VERSION_0_2  HARDWARE_MODULE_API_VERSION(0, 2)
     30 
     31 
     32 /**
     33  * The id of this module
     34  */
     35 #define POWER_HARDWARE_MODULE_ID "power"
     36 
     37 /*
     38  * Power hint identifiers passed to (*powerHint)
     39  */
     40 
     41 typedef enum {
     42     POWER_HINT_VSYNC = 0x00000001,
     43     POWER_HINT_INTERACTION = 0x00000002,
     44 } power_hint_t;
     45 
     46 /**
     47  * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
     48  * and the fields of this data structure must begin with hw_module_t
     49  * followed by module specific information.
     50  */
     51 typedef struct power_module {
     52     struct hw_module_t common;
     53 
     54     /*
     55      * (*init)() performs power management setup actions at runtime
     56      * startup, such as to set default cpufreq parameters.  This is
     57      * called only by the Power HAL instance loaded by
     58      * PowerManagerService.
     59      */
     60     void (*init)(struct power_module *module);
     61 
     62     /*
     63      * (*setInteractive)() performs power management actions upon the
     64      * system entering interactive state (that is, the system is awake
     65      * and ready for interaction, often with UI devices such as
     66      * display and touchscreen enabled) or non-interactive state (the
     67      * system appears asleep, display usually turned off).  The
     68      * non-interactive state is usually entered after a period of
     69      * inactivity, in order to conserve battery power during
     70      * such inactive periods.
     71      *
     72      * Typical actions are to turn on or off devices and adjust
     73      * cpufreq parameters.  This function may also call the
     74      * appropriate interfaces to allow the kernel to suspend the
     75      * system to low-power sleep state when entering non-interactive
     76      * state, and to disallow low-power suspend when the system is in
     77      * interactive state.  When low-power suspend state is allowed, the
     78      * kernel may suspend the system whenever no wakelocks are held.
     79      *
     80      * on is non-zero when the system is transitioning to an
     81      * interactive / awake state, and zero when transitioning to a
     82      * non-interactive / asleep state.
     83      *
     84      * This function is called to enter non-interactive state after
     85      * turning off the screen (if present), and called to enter
     86      * interactive state prior to turning on the screen.
     87      */
     88     void (*setInteractive)(struct power_module *module, int on);
     89 
     90     /*
     91      * (*powerHint) is called to pass hints on power requirements, which
     92      * may result in adjustment of power/performance parameters of the
     93      * cpufreq governor and other controls.  The possible hints are:
     94      *
     95      * POWER_HINT_VSYNC
     96      *
     97      *     Foreground app has started or stopped requesting a VSYNC pulse
     98      *     from SurfaceFlinger.  If the app has started requesting VSYNC
     99      *     then CPU and GPU load is expected soon, and it may be appropriate
    100      *     to raise speeds of CPU, memory bus, etc.  The data parameter is
    101      *     non-zero to indicate VSYNC pulse is now requested, or zero for
    102      *     VSYNC pulse no longer requested.
    103      *
    104      * POWER_HINT_INTERACTION
    105      *
    106      *     User is interacting with the device, for example, touchscreen
    107      *     events are incoming.  CPU and GPU load may be expected soon,
    108      *     and it may be appropriate to raise speeds of CPU, memory bus,
    109      *     etc.  The data parameter is unused.
    110      *
    111      * A particular platform may choose to ignore any hint.
    112      *
    113      * availability: version 0.2
    114      *
    115      */
    116     void (*powerHint)(struct power_module *module, power_hint_t hint,
    117                       void *data);
    118 } power_module_t;
    119 
    120 
    121 __END_DECLS
    122 
    123 #endif  // ANDROID_INCLUDE_HARDWARE_POWER_H
    124