Android234陀螺仪移植

1、Android2.3.4 陀螺仪移植(可以参考 )一 背景1.需求陀螺仪硬件并非接在android cpu 上，所以不存在陀螺仪驱动，而陀螺仪数据是通过用户空间的一个c 程序传过来。2.思路修改陀螺仪hal 层，在 hal 层构建 socket 客户端，在数据源的c 程序上构建socket 服务端。一旦有数据，c 程序通过socket发送数据到陀螺仪hal层，并上报。二步骤1.把 device/samsung/crespo/libsensors 目录拷贝到hardware/libhardware/modules 目录下2.修改 sensors.cpp 文件下的传感器数组定义。因只用到陀螺仪传感

2、器，把其他传感器定义删掉 cpp view plaincopystatic const struct sensor_t sSensorList = /* "KR3DM 3-axis Accelerometer","STMicroelectronics",1,SENSORS_ACCELERATION_HANDLE,SENSOR_TYPE_ACCELEROMETER, RANGE_A,CONVERT_A, 0.23f, 20000, , "AK8973 3-axisMagnetic field sensor","Asahi Ka

3、seiMicrodevices",1,SENSORS_MAGNETIC_FIELD_HANDLE,SENSOR_TYPE_MAGNETIC_FIELD, 2000.0f,CONVERT_M, 6.8f, 16667, , "AK8973 Orientation sensor", "Asahi Kasei Microdevices",1, SENSORS_ORIENTATION_HANDLE,16667, , "GP2A Light sensor","Sharp",1, SENSORS_LIGHT_HAND

4、LE,SENSOR_TYPE_LIGHT, 3000.0f, 1.0f, 0.75f, 0, , "GP2A Proximity sensor","Sharp",1, SENSORS_PROXIMITY_HANDLE,SENSOR_TYPE_PROXIMITY, 5.0f, 5.0f, 0.75f, 0, , */ "K3G Gyroscope sensor","STMicroelectronics",1, SENSORS_GYROSCOPE_HANDLE,SENSOR_TYPE_GYROSCOPE, RANGE_

5、GYRO,CONVERT_GYRO, 6.1f, 1190, ,;3.修改 sensors.cpp的 sensors_poll_context_t 结构体，删除其他的传感器定义 cppview plaincopystruct sensors_poll_context_t structsensors_poll_device_t device; / must be firstsensors_poll_context_t();sensors_poll_context_t();int activate(int handle, int enabled);int setDelay(inthandle, i

6、nt64_t ns);int pollEvents(sensors_event_t* data,int count);private:enum /light= 0,/proximity= 1,/akm= 2,/gyro= 3,gyro= 0,numSensorDrivers,numFds,;static const size_t wake = numFds -1; /wake = 1static const char WAKE_MESSAGE = 'W'struct pollfd mPollFdsnumFds;/2int mWritePipeFd;SensorBase* mSe

7、nsorsnumSensorDrivers;/ 2inthandleToDriver(int handle) const switch (handle)/*case ID_A:case ID_M:case ID_O:return akm;case ID_P:return proximity;case ID_L:return light;*/case ID_GY:return gyro;return-EINV AL; 包括构造函数： cpp viewplaincopysensors_poll_context_t:sensors_poll_context_t() /*mSensorslight =

8、 new LightSensor();mPollFdslight.fd = mSensorslight->getFd();mPollFdslight.events = POLLIN;mPollFdslight.revents = 0;mSensorsproximity = newProximitySensor();mPollFdsproximity.fd =mSensorsproximity->getFd();mPollFdsproximity.events = POLLIN;mPollFdsproximity.revents = 0;mSensorsakm = n

9、ewAkmSensor();mPollFdsakm.fd =mSensorsakm->getFd();mPollFdsakm.events =POLLIN;mPollFdsakm.revents = 0;*/LOGD("sensors_poll_context_t");mSensorsgyro =new GyroSensor();mPollFdsgyro.fd =mSensorsgyro->getFd();mPollFdsgyro.events =POLLIN;mPollFdsgyro.revents = 0;intwakeFds2;int re

10、sult = pipe(wakeFds);LOGE_IF(result<0, "error creating wake pipe (%s)",strerror(errno);fcntl(wakeFds0, F_SETFL,O_NONBLOCK);fcntl(wakeFds1, F_SETFL,O_NONBLOCK);mWritePipeFd = wakeFds1;/wake equals 1mPollFdswake.fd = wakeFds0;/storethe reading fd of the pipemPollFdswake.events =POLLIN

11、;mPollFdswake.revents = 0; 3.修改GyroSensor.cpp 的 getFd()函数，把原来的返回gyro 设备驱动的文件描述符，改为返回socket的文件描述符。cpp viewplaincopy int GyroSensor:getFd()if(mSocketFd =-1)socket_connect();returnmSocketFd; 其中 ,mSocketFd 是在 GyroSensor.h 中新定义的 socket 文件描述符， socket_connect()函数实现连接 socket服务端。我们回过头看sensors.cpp 文件的sensors_

12、poll_context_t 构造函数： cpp viewplaincopymSensorsgyro = new GyroSensor();mPollFdsgyro.fd = mSensorsgyro->getFd();mPollFdsgyro.events = POLLIN;mPollFdsgyro.revents = 0;这里初始化gyro类后，通过getFd()获取socket文件描述符，然后就可以通过poll函数对文件描述符进行读取数据，poll的读取在sensors_poll_context_t:pollEvents 函数中，代码都不用改变，像这样： cpp view

13、plaincopyintsensors_poll_context_t:pollEvents(sensors_event_t* data, intcount)/what does parameter count mean ? fuckint nbEvents = 0;int n = 0;/LOGD("sensors_poll_context_t:pollEvents");/LOGD("count=%d",count);do / see ifwe have some leftover from the last poll()for (inti=0 ; cou

14、nt && i<numSensorDrivers ; i+)SensorBase* const sensor(mSensorsi);if (mPollFdsi.revents & POLLIN) |(sensor->hasPendingEvents() int nb= sensor->readEvents(data, count);if(nb < count) / no more data forthis sensormPollFdsi.revents =0;count -= nb;nbEv

15、ents += nb;data +=nb;if (count)/ we still have some room, so try to see if wecan get/ some events immediately or just waitif we don't have/ anything to returnn = poll(mPollFds, numFds, nbEvents ? 0 : -1);if (n<0) LOGE("poll() failed (%s)",strerror(errno);return-errno;/read data

16、from pipeif (mPollFdswake.revents & POLLIN)char msg;int result= read(mPollFdswake.fd, &msg, 1);LOGE_IF(result<0, "error reading from wake pipe (%s)",strerror(errno);LOGE_IF(msg !=WAKE_MESSAGE, "unknown message on wake queue(0x%02x)", int(msg);mPollFdswake.r

17、events = 0;/ if we have events and space, go read them while (n&& count);return nbEvents;4.修改 gyro 类的构造函数， 把与设备驱动相关的那一段代码删除： cpp view plaincopyGyroSensor:GyroSensor():SensorBase(NULL, "gyro"),mEnabled(0),mInputReader(4),mHasPendingEvent(false),mEnabledTime(0),mSocketFd(-1)/

18、LOGD("GyroSensor:GyroSensor");mPendingEvent.version = sizeof(sensors_event_t);mPendingEvent.sensor = ID_GY;mPendingEvent.type =SENSOR_TYPE_GYROSCOPE;memset(mPendingEvent.data, 0, sizeof(mPendingEvent.data);/*if (data_fd) strcpy(input_sysfs_path,"/sys/class/input/");strcat(input_s

19、ysfs_path,input_name);strcat(input_sysfs_path, "/device/");input_sysfs_path_len = strlen(input_sysfs_path);enable(0, 1);*/ 5.修改 gyro 类的其他成员函数，包括 setDelay，enable，setInitialState 等函数里面的代码去全部删除：cpp view plaincopyintGyroSensor:setInitialState() /*structinput_absinfo absinfo_x;struct input_absi

20、nfo absinfo_y;struct input_absinfo absinfo_z;float value;if(!ioctl(data_fd, EVIOCGABS(EVENT_TYPE_GYRO_X),&absinfo_x) && !ioctl(data_fd, EVIOCGABS(EVENT_TYPE_GYRO_X), &absinfo_y) && !ioctl(data_fd,EVIOCGABS(EVENT_TYPE_GYRO_X), &absinfo_z)value =

21、 absinfo_x.value;mPendingEvent.data0 = value * CONVERT_GYRO_X;value = absinfo_x.value;mPendingEvent.data1 =value * CONVERT_GYRO_Y;value =absinfo_x.value;mPendingEvent.data2 = value *CONVERT_GYRO_Z;mHasPendingEvent =true;*/LOGD("GyroSensor:setInitialState");return 0; cpp view plaincopyint G

22、yroSensor:enable(int32_t, int en)/*int flags = en ? 1 : 0;if (flags !=mEnabled) int fd;strcpy(&input_sysfs_pathinput_sysfs_path_len,"enable");fd = open(input_sysfs_path, O_RDWR);if (fd >=0) char buf2;int err;buf1 = 0;if (flags) buf0= '1'mEnabledTime = getTimestamp()

23、+IGNORE_EVENT_TIME; elsebuf0 = '0'err = write(fd, buf, sizeof(buf); close(fd); mEnabled = flags; setInitialState(); return 0; return -1; */ /LOGD("GyroSensor:enable"); return 0; cppview plaincopyint GyroSensor:setDelay(int32_t handle, int64_tdelay_ns)/*int fd;strcpy(&input_

24、sysfs_pathinput_sysfs_path_len,"poll_delay");fd = open(input_sysfs_path, O_RDWR);if (fd >= 0) char buf80;sprintf(buf,"%lld", delay_ns);write(fd, buf, strlen(buf)+1);close(fd);return 0;return -1; */LOGD("GyroSensor:setDelay");return 0;6.修改 gyro 类的 readEvents 函数，这个

25、函数是最重要的函数，要从 socket 中读取 gyro 数据： cpp view plaincopyfloat value= 0;char buf2;int nread = 0;nread =read(mSocketFd, buf, 2);if(nread <=0)LOGE("GyroSensor:readEvents read error.");return 0;float value = (float)(buf0<< 8) + buf1);/LOGD("gyro_msg_handle,value=%f",v

26、alue);value *= CONVERT_GYRO_X;mPendingEvent.data0 = value;mPendingEvent.data1= value;mPendingEvent.data2 = value;*data= *mPendingEvent;return 1;sokcet服务端每次发送 2 个字节数据，因是单轴陀螺仪，所以只有1 个数据，把mPendingEvent 的 data 数据 3 个字节都填充同一数据，然后赋值给 *data，最后返回 1，表述读到 1 个数据。7.修改 libsensors 下的 Android.mk 文件的： cpp viewplain

27、copyLOCAL_MODULE := sensors.default8.编译后， 生成 sensors.default.so 文件到 lib/hw 目录，把 hw 目录下其他有sensors文字的 so 文件删除， 只留 sensors.default.so 文件，然后就可以在模拟器或设备上进行测试了，App层的Java 测试程序如下： java view plaincopypackagecom.hase.ng102.sensors;import android.R.string;importandroid.app.Activity;import android.content.Contex

28、t;import android.hardware.Sensor;importandroid.hardware.SensorEvent;importandroid.hardware.SensorEventListener;importandroid.hardware.SensorManager;import android.os.Bundle;import android.util.Log; import android.widget.TextView; public class SensorDemoActivity extends Activity /设置 LOG 标签private sta

29、tic final String TAG = "sensors"privateSensorManager sm;private TextView tv1;/* Called when the activity is first created. */Overridepublic void onCreate(Bundle savedInstanceState) super.onCreate(savedInstanceState); setContentView(R.layout.main); tv1 = (TextView)this.findViewById(R.id.tv1

30、); sm =(SensorManager)getSystemService(Context.SENSOR_SERVICE); Log.d(String.format("getSystemService %s", sm = null ? "sucess":"fail"), TAG); int sensorType = Sensor.TYPE_GYROSCOPE;sm.registerListener(myAccelerometerListener,sm.getDefaultSen sor(sensorType),SensorManager.