2 * Copyright (C) 2012 The Android Open Source Project
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #ifndef ANDROID_INCLUDE_HARDWARE_POWER_H
18 #define ANDROID_INCLUDE_HARDWARE_POWER_H
21 #include <sys/cdefs.h>
22 #include <sys/types.h>
24 #include <hardware/hardware.h>
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)
33 * The id of this module
35 #define POWER_HARDWARE_MODULE_ID "power"
38 * Power hint identifiers passed to (*powerHint)
42 POWER_HINT_VSYNC
= 0x00000001,
43 POWER_HINT_INTERACTION
= 0x00000002,
44 POWER_HINT_VIDEO_ENCODE
= 0x00000003,
45 POWER_HINT_CPU_BOOST
= 0x00000004,
49 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
50 * and the fields of this data structure must begin with hw_module_t
51 * followed by module specific information.
53 typedef struct power_module
{
54 struct hw_module_t common
;
57 * (*init)() performs power management setup actions at runtime
58 * startup, such as to set default cpufreq parameters. This is
59 * called only by the Power HAL instance loaded by
60 * PowerManagerService.
62 void (*init
)(struct power_module
*module
);
65 * (*setInteractive)() performs power management actions upon the
66 * system entering interactive state (that is, the system is awake
67 * and ready for interaction, often with UI devices such as
68 * display and touchscreen enabled) or non-interactive state (the
69 * system appears asleep, display usually turned off). The
70 * non-interactive state is usually entered after a period of
71 * inactivity, in order to conserve battery power during
72 * such inactive periods.
74 * Typical actions are to turn on or off devices and adjust
75 * cpufreq parameters. This function may also call the
76 * appropriate interfaces to allow the kernel to suspend the
77 * system to low-power sleep state when entering non-interactive
78 * state, and to disallow low-power suspend when the system is in
79 * interactive state. When low-power suspend state is allowed, the
80 * kernel may suspend the system whenever no wakelocks are held.
82 * on is non-zero when the system is transitioning to an
83 * interactive / awake state, and zero when transitioning to a
84 * non-interactive / asleep state.
86 * This function is called to enter non-interactive state after
87 * turning off the screen (if present), and called to enter
88 * interactive state prior to turning on the screen.
90 void (*setInteractive
)(struct power_module
*module
, int on
);
93 * (*powerHint) is called to pass hints on power requirements, which
94 * may result in adjustment of power/performance parameters of the
95 * cpufreq governor and other controls. The possible hints are:
99 * Foreground app has started or stopped requesting a VSYNC pulse
100 * from SurfaceFlinger. If the app has started requesting VSYNC
101 * then CPU and GPU load is expected soon, and it may be appropriate
102 * to raise speeds of CPU, memory bus, etc. The data parameter is
103 * non-zero to indicate VSYNC pulse is now requested, or zero for
104 * VSYNC pulse no longer requested.
106 * POWER_HINT_INTERACTION
108 * User is interacting with the device, for example, touchscreen
109 * events are incoming. CPU and GPU load may be expected soon,
110 * and it may be appropriate to raise speeds of CPU, memory bus,
111 * etc. The data parameter is unused.
113 * POWER_HINT_VIDEO_ENCODE
115 * The user just started or stopped recording video. When encode
116 * begins, large writes to the SD card will be done and this may
117 * cause CPU frequency to increase. The data parameter is a string
118 * with semicolon-separated 'key:value' pairs. The most common key is
119 * 'state', which takes 0 or 1 as its value. For instance, To
120 * indicate that recording is beginning, the string "state:1" would
121 * need to be used. More keys can be provided depending on the data
122 * that is to be passed.
124 * POWER_HINT_CPU_BOOST
126 * An operation is happening where it would be ideal for the CPU to
127 * be boosted for a specific duration. The data parameter is an
128 * integer value of the boost duration in microseconds.
130 * A particular platform may choose to ignore any hint.
132 * availability: version 0.2
135 void (*powerHint
)(struct power_module
*module
, power_hint_t hint
,
142 #endif // ANDROID_INCLUDE_HARDWARE_POWER_H