8.3 Android灯光系统_编写HAL_lights.c

　　

注意在led-classes.c中定义的led_class_attrs[]所建立的文件的属性应该改为0666,否则应用程序无权操作它

同时ledtrig-time.c里面对应新建的那几个delay_on/delay_off也要改为0666,这样才能写它

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  //参考google上搜索到的lights.c,我们的开发上只有HAL的so库，在vendor/friendly-arm/tiny4412/proprietary/lights_tiny4412.so

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

设置LED状态：
struct light_state_t {
/**
* The color of the LED in ARGB.
*
* Do your best here.
* - If your light can only do red or green, if they ask for blue,
* you should do green.
* - If you can only do a brightness ramp, then use this formula:
* unsigned char brightness = ((77*((color>>16)&0x00ff))
* + (150*((color>>8)&0x00ff)) + (29*(color&0x00ff))) >> 8;
* - If you can only do on or off, 0 is off, anything else is on.
*
* The high byte should be ignored. Callers will set it to 0xff (which
* would correspond to 255 alpha).
*/
unsigned int color; // 把灯设为什么颜色, 或 把LCD的亮度设为什么

/**
* See the LIGHT_FLASH_* constants
*/
int flashMode; // 是否闪烁, LIGHT_FLASH_NONE表示不闪
int flashOnMS; // 亮的时间
int flashOffMS;// 灭的时间

/**
* Policy used by the framework to manage the light's brightness.
* Currently the values are BRIGHTNESS_MODE_USER and BRIGHTNESS_MODE_SENSOR.
*/
int brightnessMode; // 表示LCD的背光亮度模式
};

lights.c文件

注意在led-classes.c中定义的led_class_attrs[]所建立的文件的属性应该改为0666,否则应用程序无权操作它

#define LOG_TAG “lights”

#define LOG_NDEBUG 0  //加上这句就可以用ALOGV来打印了，否则打印信息被忽略

#include <hardware/led_hal.h>

#include <hardware/hardware.h>

......还有很多头文件.........

//HAL里面操作led等就是往这些文件里面写值来完成的

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";//反汇编厂家提供的HAL层SO，lights_tiny4412.so,可以看到对背光灯的操作是该文件，在内核中搜索“backlight-1wire”,发现其是对应drivers/input/touchscreen/tiny4412_1wire_host.c中注册的设备，其是一个miscdevice，提供了file_operation结构体

static pthread_one_t g_init = PTHREAD_ONCE_INIT;

static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER;

//通知灯和电池灯公用一个硬件

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)

　　　　{

　　　　　　already_warned = 1;

　　　　}

　　　　return -errno;

　　}

　　char buffer[20];

　　int bytes = snprintf(buffer,sizeof(buffer),"%s\n",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)

　　　　{

　　　　　　already_warned = 1;

　　　　}

　　　　return -errno;

　　}

　　char buffer[20];

　　int bytes = snprintf(buffer,sizeof(buffer),"%s\n",value);

　　int written = write(fd,buffer,bytes);

　　close(fd);

　　return written == -1?-errno:0;

}

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)))>>

}

static int set_light_backlight(struct light_device_t *dev,,struct light_state_t *state){

　　int brightness = rgb_to_brightness(state);

　　pthread_mutex_lock(&g_lock);

　　//brightness在这里的范围是0-255，但是设备文件能接受的是0-127

　　write_int(LCD_BACKLIGHT_FILR,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,"trigger");

　　　　write_string(GREEN_LED_FILE_TRIGGER,"trigger");

　　　　write_string(BLUE_LED_FILE_TRIGGER,"trigger");

　　　　write_int(RED_LED_FILR_DELAYON,delayOn);

　　　　write_int(GREEN_LED_FILR_DELAYON,delayOn);

　　　　write_int(BLUE_LED_FILR_DELAYON,delayOn);

　　　　write_int(RED_LED_FILR_DELAYOFF,delayOff);

　　　　write_int(GREEN_LED_FILR_DELAYOFF,delayOff);

　　　　write_int(BLUE_LED_FILR_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)){//优先设置通知灯

　　　　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 *state){

　　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 *state){

　　pthread_mutex_lock(&g_lock);

　　g_notification = *state;

　　handle_shared_battery_locked(dev);

　　pthread_mutex_unlock(&g_lock);

　　return 0;

}

void init_globals(){

　　pthread_mutex_init(&g_lock,NULL);

}

static int close_lights(struct light_device_t* dev){

}

static int open_lights(const struct hw_module_t *module,const char *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),GPKERNEL);

　　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;

　　*device = &led_dev //led_dev 的第一个成员就是hw_device_t ，他们地址一样

}

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 ="Snoy_lights_module",

　　.methods = lights_module_methods ;

}

在lights.c下添加Android.mk

Android.mk内容如下：

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE := lights.tiny4412;

LOCAL_MODULE_RELATIVE_PATH :=hw  //指定了so存在的目录在/system/lib/hw下

LOCAL_C_INCLUDES := hardware/libhardware  //头文件

LOCAL__SRC_FILES := lights.c  //源文件

LOCAL_SHARED_LIBRARIES := liblog

LOCAL_MODULE_TAGS := eng

include $(BUILD_SHARED_LIBRARY)

上传HAL：lights.c

　hardware/libhardware/modules/lights/lights.c

　hardware/libhardware/modules/lights/Android.mk

修改：

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

注释掉device-tiny4412.mk里面的(应该是去掉厂家提供的HAL)

ifeq ($(BOARD_USES_PWMLIGHTS),false)

#PRODUCT_COPY_FILES +=\

#　　　　　　$(VENDOR_PATH)/proprietary/lights.tiny4412.so:system/lib/hw/lights.tiny4412.so

endif

编译：

.setenv//先设置环境变量

lunch//执行后选择23 full_tiny4412_eng  这里的eng对应的Android.mk里面设置的eng

mmm hardware/libhardware/modules/lights -B  //强制编译C库

make snod

./gen-img.sh

对比下厂家提供HAL和我们自己生成的HAL，会发现不一样，同时该命令也能确保我们提供的lights.c已经编进system.img

diff vendor/friendly-arm/tiny4412/proprietary/lights.tiny4412.so  out/target/product/tiny4412/system/lib/hw/lights.tiny4412.so

更新system.img 和上一节中得到的zImage