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 * The id of this module
33 */
34#define POWER_HARDWARE_MODULE_ID "power"
35
36/*
37 * Power hint identifiers passed to (*powerHint)
38 */
39
40typedef enum {
41    POWER_HINT_VSYNC = 0x00000001,
42    POWER_HINT_INTERACTION = 0x00000002,
43    /* DO NOT USE POWER_HINT_VIDEO_ENCODE/_DECODE!  They will be removed in
44     * KLP.
45     */
46    POWER_HINT_VIDEO_ENCODE = 0x00000003,
47    POWER_HINT_VIDEO_DECODE = 0x00000004
48} power_hint_t;
49
50/**
51 * Every hardware module must have a data structure named HAL_MODULE_INFO_SYM
52 * and the fields of this data structure must begin with hw_module_t
53 * followed by module specific information.
54 */
55typedef struct power_module {
56    struct hw_module_t common;
57
58    /*
59     * (*init)() performs power management setup actions at runtime
60     * startup, such as to set default cpufreq parameters.  This is
61     * called only by the Power HAL instance loaded by
62     * PowerManagerService.
63     */
64    void (*init)(struct power_module *module);
65
66    /*
67     * (*setInteractive)() performs power management actions upon the
68     * system entering interactive state (that is, the system is awake
69     * and ready for interaction, often with UI devices such as
70     * display and touchscreen enabled) or non-interactive state (the
71     * system appears asleep, display usually turned off).  The
72     * non-interactive state is usually entered after a period of
73     * inactivity, in order to conserve battery power during
74     * such inactive periods.
75     *
76     * Typical actions are to turn on or off devices and adjust
77     * cpufreq parameters.  This function may also call the
78     * appropriate interfaces to allow the kernel to suspend the
79     * system to low-power sleep state when entering non-interactive
80     * state, and to disallow low-power suspend when the system is in
81     * interactive state.  When low-power suspend state is allowed, the
82     * kernel may suspend the system whenever no wakelocks are held.
83     *
84     * on is non-zero when the system is transitioning to an
85     * interactive / awake state, and zero when transitioning to a
86     * non-interactive / asleep state.
87     *
88     * This function is called to enter non-interactive state after
89     * turning off the screen (if present), and called to enter
90     * interactive state prior to turning on the screen.
91     */
92    void (*setInteractive)(struct power_module *module, int on);
93
94    /*
95     * (*powerHint) is called to pass hints on power requirements, which
96     * may result in adjustment of power/performance parameters of the
97     * cpufreq governor and other controls.  The possible hints are:
98     *
99     * POWER_HINT_VSYNC
100     *
101     *     Foreground app has started or stopped requesting a VSYNC pulse
102     *     from SurfaceFlinger.  If the app has started requesting VSYNC
103     *     then CPU and GPU load is expected soon, and it may be appropriate
104     *     to raise speeds of CPU, memory bus, etc.  The data parameter is
105     *     non-zero to indicate VSYNC pulse is now requested, or zero for
106     *     VSYNC pulse no longer requested.
107     *
108     * POWER_HINT_INTERACTION
109     *
110     *     User is interacting with the device, for example, touchscreen
111     *     events are incoming.  CPU and GPU load may be expected soon,
112     *     and it may be appropriate to raise speeds of CPU, memory bus,
113     *     etc.  The data parameter is unused.
114     *
115     * A particular platform may choose to ignore any hint.
116     *
117     * availability: version 0.2
118     *
119     */
120    void (*powerHint)(struct power_module *module, power_hint_t hint,
121                      void *data);
122} power_module_t;
123
124
125__END_DECLS
126
127#endif  // ANDROID_INCLUDE_HARDWARE_POWER_H
128