一、android灯光系统框架：
Java: frameworks/base/services/core/java/com/android/server/lights/LightsService.java
JNI: frameworks/base/services/core/jni/com_android_server_lights_LightsService.cpp
Hal: lights.c
默认配色：frameworks/base/core/res/res/values/config.xml
电池灯：frameworks/base/services/core/java/com/android/server/BatteryService.java
通知灯：frameworks/base/services/core/java/com/android/server/notification/NotificationManagerService.java
怎么写LIGHTS HAL
a. 实现一个名为HMI的hw_module_t结构体
b. 实现一个open函数, 它会根据name返回一个light_device_t结构体
c. 实现多个light_device_t结构体，每一个对应一个DEVICE
light_device_t结构体里第1个成员是hw_device_t结构体, 紧接着一个set_light函数
二、代码lights.c：
/* * Copyright (C) 2008 The Android Open Source Project * Copyright (C) 2011 Diogo Ferreira <defer@cyanogenmod.com> * Copyright (C) 2012 Andreas Makris <andreas.makris@gmail.com> * Copyright (C) 2012 The CyanogenMod Project <http://www.cyanogenmod.com> * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #define LOG_NDEBUG 0 #define LOG_TAG "lights" #include <cutils/log.h> #include <stdint.h> #include <string.h> #include <unistd.h> #include <errno.h> #include <fcntl.h> #include <pthread.h> #include <sys/ioctl.h> #include <sys/types.h> #include <hardware/lights.h> char const*const RED_LED_FILE = "/sys/class/leds/led1/brightness"; char const*const GREEN_LED_FILE = "/sys/class/leds/led2/brightness"; char const*const BLUE_LED_FILE = "/sys/class/leds/led3/brightness"; char const*const RED_LED_FILE_TRIGGER = "/sys/class/leds/led1/trigger"; char const*const GREEN_LED_FILE_TRIGGER = "/sys/class/leds/led2/trigger"; char const*const BLUE_LED_FILE_TRIGGER = "/sys/class/leds/led3/trigger"; char const*const RED_LED_FILE_DELAYON = "/sys/class/leds/led1/delay_on"; char const*const GREEN_LED_FILE_DELAYON = "/sys/class/leds/led2/delay_on"; char const*const BLUE_LED_FILE_DELAYON = "/sys/class/leds/led3/delay_on"; char const*const RED_LED_FILE_DELAYOFF = "/sys/class/leds/led1/delay_off"; char const*const GREEN_LED_FILE_DELAYOFF= "/sys/class/leds/led2/delay_off"; char const*const BLUE_LED_FILE_DELAYOFF = "/sys/class/leds/led3/delay_off"; char const*const LCD_BACKLIGHT_FILE = "/dev/backlight-1wire"; /* Synchronization primities */ static pthread_once_t g_init = PTHREAD_ONCE_INIT; static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER; /* Mini-led state machine */ static struct light_state_t g_notification; static struct light_state_t g_battery; static int write_int (const char *path, int value) { int fd; static int already_warned = 0; fd = open(path, O_RDWR); if (fd < 0) { if (already_warned == 0) { ALOGE("write_int failed to open %s ", path); already_warned = 1; } return -errno; } char buffer[20]; int bytes = snprintf(buffer, sizeof(buffer), "%d ", value); int written = write (fd, buffer, bytes); close(fd); return written == -1 ? -errno : 0; } static int write_string (const char *path, const char *value) { int fd; static int already_warned = 0; fd = open(path, O_RDWR); if (fd < 0) { if (already_warned == 0) { ALOGE("write_string failed to open %s ", path); already_warned = 1; } return -errno; } char buffer[20]; int bytes = snprintf(buffer, sizeof(buffer), "%s ", value); int written = write (fd, buffer, bytes); close(fd); return written == -1 ? -errno : 0; } /* Color tools */ static int is_lit (struct light_state_t const* state) { return state->color & 0x00ffffff; } static int rgb_to_brightness (struct light_state_t const* state) { int color = state->color & 0x00ffffff; return ((77*((color>>16)&0x00ff)) + (150*((color>>8)&0x00ff)) + (29*(color&0x00ff))) >> 8; } /* The actual lights controlling section */ static int set_light_backlight (struct light_device_t *dev, struct light_state_t const *state) { int brightness = rgb_to_brightness(state); ALOGV("%s brightness=%d color=0x%08x", __func__,brightness,state->color); pthread_mutex_lock(&g_lock); /* brightness 0-255 */ /* LCD_BACKLIGHT_FILE能接收是0-127 */ write_int (LCD_BACKLIGHT_FILE, brightness/2); pthread_mutex_unlock(&g_lock); return 0; } static void set_shared_light_locked (struct light_device_t *dev, struct light_state_t *state) { int r, g, b; int delayOn,delayOff; r = (state->color >> 16) & 0xFF; g = (state->color >> 8) & 0xFF; b = (state->color) & 0xFF; delayOn = state->flashOnMS; delayOff = state->flashOffMS; if (state->flashMode != LIGHT_FLASH_NONE) { write_string (RED_LED_FILE_TRIGGER, "timer"); write_string (GREEN_LED_FILE_TRIGGER, "timer"); write_string (BLUE_LED_FILE_TRIGGER, "timer"); write_int (RED_LED_FILE_DELAYON, delayOn); write_int (GREEN_LED_FILE_DELAYON, delayOn); write_int (BLUE_LED_FILE_DELAYON, delayOn); write_int (RED_LED_FILE_DELAYOFF, delayOff); write_int (GREEN_LED_FILE_DELAYOFF, delayOff); write_int (BLUE_LED_FILE_DELAYOFF, delayOff); } else { write_string (RED_LED_FILE_TRIGGER, "none"); write_string (GREEN_LED_FILE_TRIGGER, "none"); write_string (BLUE_LED_FILE_TRIGGER, "none"); } write_int (RED_LED_FILE, r); write_int (GREEN_LED_FILE, g); write_int (BLUE_LED_FILE, b); } static void handle_shared_battery_locked (struct light_device_t *dev) { if (is_lit (&g_notification)) { set_shared_light_locked (dev, &g_notification); } else { set_shared_light_locked (dev, &g_battery); } } static int set_light_battery (struct light_device_t *dev, struct light_state_t const* state) { ALOGV("%s flashMode=%d onMS = %d offMS = %d color=0x%08x", __func__,state->flashMode,state->flashOnMS,state->flashOffMS,state->color); pthread_mutex_lock (&g_lock); g_battery = *state; handle_shared_battery_locked(dev); pthread_mutex_unlock (&g_lock); return 0; } static int set_light_notifications (struct light_device_t *dev, struct light_state_t const* state) { ALOGV("%s flashMode=%d onMS = %d offMS = %d color=0x%08x", __func__,state->flashMode,state->flashOnMS,state->flashOffMS,state->color); pthread_mutex_lock (&g_lock); g_notification = *state; handle_shared_battery_locked(dev); pthread_mutex_unlock (&g_lock); return 0; } /* Initializations */ void init_globals () { pthread_mutex_init (&g_lock, NULL); } /* Glueing boilerplate */ static int close_lights (struct light_device_t *dev) { if (dev) free(dev); return 0; } static int open_lights (const struct hw_module_t* module, char const* name, struct hw_device_t** device) { int (*set_light)(struct light_device_t* dev, struct light_state_t const *state); if (0 == strcmp(LIGHT_ID_BACKLIGHT, name)) { set_light = set_light_backlight; } else if (0 == strcmp(LIGHT_ID_BATTERY, name)) { set_light = set_light_battery; } else if (0 == strcmp(LIGHT_ID_NOTIFICATIONS, name)) { set_light = set_light_notifications; } else { return -EINVAL; } pthread_once (&g_init, init_globals); struct light_device_t *dev = malloc(sizeof (struct light_device_t)); memset(dev, 0, sizeof(*dev)); dev->common.tag = HARDWARE_DEVICE_TAG; dev->common.version = 0; dev->common.module = (struct hw_module_t*)module; dev->common.close = (int (*)(struct hw_device_t*))close_lights; dev->set_light = set_light; *device = (struct hw_device_t*)dev; return 0; } static struct hw_module_methods_t lights_module_methods = { .open = open_lights, }; struct hw_module_t HAL_MODULE_INFO_SYM = { .tag = HARDWARE_MODULE_TAG, .version_major = 1, .version_minor = 0, .id = LIGHTS_HARDWARE_MODULE_ID, .name = "Sony lights module", .author = "Diogo Ferreira <defer@cyanogenmod.com>, Andreas Makris <Andreas.Makris@gmail.com>", .methods = &lights_module_methods, };
三、Android.mk
# Copyright (C) 2012 The Android Open Source Project # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := lights.tiny4412 # HAL module implementation stored in # hw/<VIBRATOR_HARDWARE_MODULE_ID>.default.so LOCAL_MODULE_RELATIVE_PATH := hw LOCAL_C_INCLUDES := hardware/libhardware LOCAL_SRC_FILES := lights.c LOCAL_SHARED_LIBRARIES := liblog LOCAL_MODULE_TAGS := eng include $(BUILD_SHARED_LIBRARY)