JNI文件：com_Android_server_LedService.cpp

註冊本地方法，會加載HAL文件：

3. 編寫android燈光系統的hal程序

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

默認配色：frameworks/base/core/res/res/values/config.xml
電池燈：frameworks/base/services/core/java/com/android/server/BatteryService.java
通知燈：frameworks/base/services/core/java/com/android/server/notification/NotificationManagerService.java

怎麽寫LIGHTS HAL
a. 實現一個名為HMI的hw_module_t結構體
b. 實現一個open函數, 它會根據name返回一個light_device_t結構體
c. 實現多個light_device_t結構體，每一個對應一個DEVICE
light_device_t結構體裏第1個成員是hw_device_t結構體, 緊接著一個set_light函數

HAL: lights.c

把新文件上傳到服務器, 所在目錄:
hardware/libhardware/modules/lights/led_hal.c
hardware/libhardware/modules/lights/Android.mk

 

Android.mk內容如下:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := lights.tiny4412
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)


修改
vi vendor
 
/friendly-arm/tiny4412/device-tiny4412.mk

ifeq ($(BOARD_USES_PWMLIGHTS),false)
#PRODUCT_COPY_FILES += #       $(VENDOR_PATH)/proprietary/lights.tiny4412.so:system/lib/hw/lights.tiny4412.so
endif

編譯：
執行mmm命令之前先執行這幾個命令：

$ mmm hardware/libhardware/modules/lights
$ make snod
$ ./gen-img.sh

用這個命令確保我們提供的lights.c已經編進system.img:
diff vendor/friendly-arm/tiny4412/proprietary/lights.tiny4412.so out/target/product/tiny4412/system/lib/hw/lights.tiny4412.so

沒有修改代碼進行強制編譯 -B

內核也需要修改：修改權限
1. drivers/leds/led-class.c: 0644 改為 0666
static struct device_attribute led_class_attrs[] = {
    __ATTR(brightness, 0666, led_brightness_show, led_brightness_store),
    __ATTR(max_brightness, 0444, led_max_brightness_show, NULL),
#ifdef CONFIG_LEDS_TRIGGERS
    __ATTR(trigger, 0666, led_trigger_show, led_trigger_store),
#endif
    __ATTR_NULL,
};

2. drivers/leds/ledtrig-timer.c: 0644 改為 0666
#if defined(CONFIG_MACH_IPCAM)
static DEVICE_ATTR(delay_on, 0666, led_delay_on_show, led_delay_on_store);
static DEVICE_ATTR(delay_off, 0666, led_delay_off_show, led_delay_off_store);
#else
static DEVICE_ATTR(delay_on, 0666, led_delay_on_show, led_delay_on_store);
static DEVICE_ATTR(delay_off, 0666, led_delay_off_show, led_delay_off_store);
#endif

make zImage



用這個命令確保我們提供的lights.c已經編進system.img:
diff vendor/friendly-arm/tiny4412/proprietary/lights.tiny4412.so out/target/product/tiny4412/system/lib/hw/lights.tiny4412.so


logcat lights:V *:S

第4課第3節_Android燈光系統_編寫HAL_lights.c