lights.h
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1 /*
2  * Copyright (C) 2008 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_LIGHTS_INTERFACE_H
18 #define ANDROID_LIGHTS_INTERFACE_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 /**
29  * The id of this module
30  */
31 #define LIGHTS_HARDWARE_MODULE_ID "lights"
32 
33 /**
34  * Header file version.
35  */
36 #define LIGHTS_HEADER_VERSION 1
37 
38 /**
39  * Device API version 0.0-1.0
40  *
41  * Base version for the device API in the lights HAL: all versions less than
42  * 2.0 are treated as being this version.
43  */
44 #define LIGHTS_DEVICE_API_VERSION_1_0 HARDWARE_DEVICE_API_VERSION_2(1, 0, LIGHTS_HEADER_VERSION)
45 
46 /**
47  * Device API version 2.0
48  *
49  * Devices reporting this version or higher may additionally support the
50  * following modes:
51  * - BRIGHTNESS_MODE_LOW_PERSISTENCE
52  */
53 #define LIGHTS_DEVICE_API_VERSION_2_0 HARDWARE_DEVICE_API_VERSION_2(2, 0, LIGHTS_HEADER_VERSION)
54 
55 /*
56  * These light IDs correspond to logical lights, not physical.
57  * So for example, if your INDICATOR light is in line with your
58  * BUTTONS, it might make sense to also light the INDICATOR
59  * light to a reasonable color when the BUTTONS are lit.
60  */
61 #define LIGHT_ID_BACKLIGHT "backlight"
62 #define LIGHT_ID_KEYBOARD "keyboard"
63 #define LIGHT_ID_BUTTONS "buttons"
64 #define LIGHT_ID_BATTERY "battery"
65 #define LIGHT_ID_NOTIFICATIONS "notifications"
66 #define LIGHT_ID_ATTENTION "attention"
67 
68 /*
69  * These lights aren't currently supported by the higher
70  * layers, but could be someday, so we have the constants
71  * here now.
72  */
73 #define LIGHT_ID_BLUETOOTH "bluetooth"
74 #define LIGHT_ID_WIFI "wifi"
75 
76 /* ************************************************************************
77  * Flash modes for the flashMode field of light_state_t.
78  */
79 
80 #define LIGHT_FLASH_NONE 0
81 
82 /**
83  * To flash the light at a given rate, set flashMode to LIGHT_FLASH_TIMED,
84  * and then flashOnMS should be set to the number of milliseconds to turn
85  * the light on, followed by the number of milliseconds to turn the light
86  * off.
87  */
88 #define LIGHT_FLASH_TIMED 1
89 
90 /**
91  * To flash the light using hardware assist, set flashMode to
92  * the hardware mode.
93  */
94 #define LIGHT_FLASH_HARDWARE 2
95 
96 /**
97  * Light brightness is managed by a user setting.
98  */
99 #define BRIGHTNESS_MODE_USER 0
100 
101 /**
102  * Light brightness is managed by a light sensor.
103  */
104 #define BRIGHTNESS_MODE_SENSOR 1
105 
106 /**
107  * Use a low-persistence mode for display backlights.
108  *
109  * When set, the device driver must switch to a mode optimized for low display
110  * persistence that is intended to be used when the device is being treated as a
111  * head mounted display (HMD). The actual display brightness in this mode is
112  * implementation dependent, and any value set for color in light_state may be
113  * overridden by the HAL implementation.
114  *
115  * For an optimal HMD viewing experience, the display must meet the following
116  * criteria in this mode:
117  * - Gray-to-Gray, White-to-Black, and Black-to-White switching time must be ≤ 3 ms.
118  * - The display must support low-persistence with ≤ 3.5 ms persistence.
119  * Persistence is defined as the amount of time for which a pixel is
120  * emitting light for a single frame.
121  * - Any "smart panel" or other frame buffering options that increase display
122  * latency are disabled.
123  * - Display brightness is set so that the display is still visible to the user
124  * under normal indoor lighting.
125  * - The display must update at 60 Hz at least, but higher refresh rates are
126  * recommended for low latency.
127  *
128  * This mode will only be used with light devices of type LIGHT_ID_BACKLIGHT,
129  * and will only be called by the Android framework for light_device_t
130  * implementations that report a version >= 2.0 in their hw_device_t common
131  * fields. If the device version is >= 2.0 and this mode is unsupported, calling
132  * set_light with this mode must return the negative error code -ENOSYS (-38)
133  * without altering any settings.
134  *
135  * Available only for version >= LIGHTS_DEVICE_API_VERSION_2_0
136  */
137 #define BRIGHTNESS_MODE_LOW_PERSISTENCE 2
138 
139 /**
140  * The parameters that can be set for a given light.
141  *
142  * Not all lights must support all parameters. If you
143  * can do something backward-compatible, you should.
144  */
146  /**
147  * The color of the LED in ARGB.
148  *
149  * Do your best here.
150  * - If your light can only do red or green, if they ask for blue,
151  * you should do green.
152  * - If you can only do a brightness ramp, then use this formula:
153  * unsigned char brightness = ((77*((color>>16)&0x00ff))
154  * + (150*((color>>8)&0x00ff)) + (29*(color&0x00ff))) >> 8;
155  * - If you can only do on or off, 0 is off, anything else is on.
156  *
157  * The high byte should be ignored. Callers will set it to 0xff (which
158  * would correspond to 255 alpha).
159  */
160  unsigned int color;
161 
162  /**
163  * See the LIGHT_FLASH_* constants
164  */
168 
169  /**
170  * Policy used by the framework to manage the light's brightness.
171  * Currently the values are BRIGHTNESS_MODE_USER and BRIGHTNESS_MODE_SENSOR.
172  */
174 };
175 
178 
179  /**
180  * Set the provided lights to the provided values.
181  *
182  * Returns: 0 on succes, error code on failure.
183  */
184  int (*set_light)(struct light_device_t* dev,
185  struct light_state_t const* state);
186 };
187 
188 
189 __END_DECLS
190 
191 #endif // ANDROID_LIGHTS_INTERFACE_H
192 
int flashMode
Definition: lights.h:165
int flashOnMS
Definition: lights.h:166
int flashOffMS
Definition: lights.h:167
unsigned int color
Definition: lights.h:160
int(* set_light)(struct light_device_t *dev, struct light_state_t const *state)
Definition: lights.h:184
struct hw_device_t common
Definition: lights.h:177
int brightnessMode
Definition: lights.h:173