学步园

1. frameworks/base/services/jni/com_android_server_LightsService.cpp, it is interface for java

static void setLight_native(JNIEnv *env, jobject clazz, int ptr,
        int light, int colorARGB, int flashMode, int onMS, int offMS, int brightnessMode)
{
    Devices* devices = (Devices*)ptr;
    light_state_t state;

    if (light < 0 || light >= LIGHT_COUNT || devices->lights[light] == NULL) {
        return ;
    }

    memset(&state, 0, sizeof(light_state_t));
    state.color = colorARGB;
    state.flashMode = flashMode;
    state.flashOnMS = onMS;
    state.flashOffMS = offMS;
    state.brightnessMode = brightnessMode;

    {
        ALOGD_IF_SLOW(50, "Excessive delay setting light");
        devices->lights[light]->set_light(devices->lights[light], &state);
    }
}

2. hardware/qcom/display/liblight/lights.c

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;   // backlight
    else if (0 == strcmp(LIGHT_ID_BATTERY, name))
        set_light = set_light_battery;     // battery charge
    else if (0 == strcmp(LIGHT_ID_NOTIFICATIONS, name))
        set_light = set_light_notifications; // notifications for missed calls ,messages and so on.
    else if (0 == strcmp(LIGHT_ID_ATTENTION, name))
        set_light = set_light_attention;   // not sure
    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,
};

/*
 * The lights Module
 */
struct hw_module_t HAL_MODULE_INFO_SYM = {
    .tag = HARDWARE_MODULE_TAG,
    .version_major = 1,
    .version_minor = 0,
    .id = LIGHTS_HARDWARE_MODULE_ID,
    .name = "lights Module",
    .author = "Google, Inc.",
    .methods = &lights_module_methods,
};

Charging status precedes the status of missed call.

Compile modules:

# . ./build/envsetup.sh
# lunch num
# make lights.msm8960