Android驱动开发实例(控制LED灯)(精)

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1、Android驱动例子（LED灯控制）本例子，讲述在Android2.1上完全自已开发一个驱动去控制硬件口并写应用测试该驱动，通过这样一个例子，解析android下的驱动开发流程的应用调用流程，可以说是很好的入门引导要达到的效果：通过Android的应用，调用驱动程序，在开发板上控制4个LED的亮灭。一、硬件原理rii11F|LfeOi1电UFlelEd11:一TSiWLED111圳制：ldiiVSATj1ITFlLED111LED配hi生鼻追“11p如上图，通过4个IO口控制这LED,低电平LED亮,这4个IO口分另U是GPM1,GPM2,GPM3,GPM4,二、驱动程序1、在kernel文

2、件夹下的driver目录，新键驱动文件夹#cdkernel_Android_2.6.28.6/drivers进到开发板的kernel目录，建驱动文件夹#mkdirledtest2、在/driver/ledtest目录下，新建leddriver.c,leddriver.h,Kconfig,Makefile等4个文件leddriver.c1. #include2. #include3. #include4. #include/*Forinit/exit/.*/5. #include6. #include7. #include8. #include9. #include10.#include11.#

3、include12.#include13.#include14.#include15.#include16.#include17.#include/forregisterchrdev(18.#include19.#include20.#includeleddriver.h21.#include/*ForMODULEALIASMISCDEV22.(WATCHDOGMINOR*/23.#include/*Forthewatchdogspecificitems*/24.#include/*Forfileoperations*/25.#defineViberatorMAJOR97/?ee?o?26.#

4、defineSCULLNRDEVS427.#defineSCULLQUANTUM400028.#defineSCULLQSET100029./doastheGIOdriver30. #defineDEVCOUNT431. #defineGIO_MINOR2/*GIOminorno.*/32. staticdev_tdev;/ee?p?p?ee?o?33. staticstructcdev*cdev_p;34. staticintopenCnt;35. /e?a?36. intVIB_major=97;/weasigmentitfortest37. intVIB_minor=0;38. intV

5、IB_nr_devs=SCULL_NR_DEVS;39. intVIB_quantum=SCULL_QUANTUM;40. intVIB_qset=SCULL_QSET;41.41. staticstructclass*vib_dev_class;42. #defineGPNCONS3C64XX_GPNCON43. #defineGPNDATS3C64XX_GPNDAT44. #defineGPNPUDS3C64XX_GPNPUD45. #defineGPMCONS3C64XX_GPMCON46. #defineGPMDATS3C64XX_GPMDAT47. #defineGPMPUDS3C6

6、4XX_GPMPUD49.48. #defineVIB_ON0x1149. #defineVIB_OFF0x2250. staticconststructfile_operationsGPIO_Viberator_ctl_ops=51. .owner=THIS_MODULE,52. .open=GPIO_VIB_open,53. .read=GPIO_VIB_read,54. .write=GPIO_VIB_write,55. .ioctl=GPIO_VIB_ioctl,56. .release=GPIO_VIB_release,57. ;58. ssize_tGPIO_VIB_read(st

7、ructfile*file,char*buf,size_tcount,loff_t*f_ops59. 60. printk(GPIO_VIB_readrn;63.gpiodirectionoutput(S3C64XXGPM(3,0;/64.returncount;65.66.ssizetGPIOVIBwrite(structfile*file,constcharcount,lofft*fops*buf,sizet67.68.printk(GPIOVIBwritern;69.gpiodirectionoutput(S3C64XXGPM(3,1;/70.returncount;71.72.73.i

8、nt/ssizetGPIOVIBioctl(structinode*inode,structcmd,longdatafile*file,unsigned74.intstaticintGPIOVIBioctl(structinode*inode,structcmd,unsignedlongargfile*file,unsigned75.76.printk(KERNERRVIB:GPIOVIBioctl-CMD=%xn,cmd;77.switch(cmd78.79.caseVIBON:80.gpiodirectionoutput(S3C64XXGPM(1,0;/81.gpiodirectionou

9、tput(S3C64XXGPM(2,0;/82.gpiodirectionoutput(S3C64XXGPM(3,0;/83.gpiodirectionoutput(S3C64XXGPM(4,1;/84.printk(KERNERRVIB:GPIOVIBioctl-VIBONn;85.break;86.caseVIBOFF:87.88.printk(KERNERRVIB:GPIOVIBioctl-VIBOFFn;89.gpiodirectionoutput(S3C64XXGPM(1,1;/90.gpiodirectionoutput(S3C64XXGPM(2,1;/91.gpiodirecti

10、onoutput(S3C64XXGPM(3,1;/92.gpiodirectionoutput(S3C64XXGPM(4,0;/93.break;94.95.default:break;96.97.98./gpio_free(S3C64XX_GPN(7;99.100.ssizetGPIOVIBopen(structinode*inode,structfile*file101.102./?eey103./MODINCUSECOUNT;104.printk(GPIOVIBopen(n;105.return0;106.107.ssizetGPIOVIBrelease(structinode*inod

11、e,structfile*file108.109./MOD_DEC_USE_COUNT;/?eey?110.printk(GPIOVIBrelease(n;111.return0;112.113.staticintGPIOVIBCTLinit(void114.115.intret=-ENODEV;116.interror;117.printk(rn;118./3?e?_u119.s3c_gpio_cfgpin(S3C64XX_GPM(1,S3C_GPIO_SFN(1;/GPM1Output120.s3c_gpio_cfgpin(S3C64XX_GPM(2,S3C_GPIO_SFN(1;/GPM

12、2Output121.s3c_gpio_cfgpin(S3C64XX_GPM(3,S3C_GPIO_SFN(1;/GPM3Output122.s3c_gpio_cfgpin(S3C64XX_GPM(4,S3C_GPIO_SFN(1;/GPM4Output123.#if1/*?21?e?xC2a?y?_*/124.ret=registerchrdev(ViberatorMAJOR,viberator,&GPIOViberatorctlops;125.if(ret0126.printk(KERNERRVIB:unabletogetmajor%dn,ret;127.returnret;128.129

13、.？uclclass130.vibdevclass=classcreate(THISMODULE,viberator;131.if(ISERR(vibdevclass132.unregisterchrdev(ViberatorMAJOR,capi20;133.returnPTRERR(vibdevclass;134.135./?“?仲？?136.devicecreate(vibdevclass,NULL,MKDEV(ViberatorMAJOR,0,NULL,vib;137./createapointunder/dev/class/vib138./i_1yea自？2?y?_?6?o6?i?自？

14、U/dev/class/eU3euc1vib?Up?6|6?3iDd?ed2uxtu2ux?aup?i_1yuc1open,write,?e?e?ed?ro6?p?6|6?e?ay3iDd?readpeo_ey2ux139.return0；140.#endif141.#if0/*xC2a?i?*/142.if(error=allocchrdevregion(&dev,0,DEVCOUNT,vibrateops=&GPIOViberatorctlops;152.error=cdevadd(cdevp,dev,DEVCOUNT;153.if(error154.printk(KERNERR155.V

15、IB:Couldntcdevadd,error=%dn,error;156.return1;157.158.159.vibdevclass=classcreate(THISMODULE,vib-dev;160.if(ISERR(vibdevclass161.res=PTRERR(vibdevclass;162.gotooutunregclass;163.164.return0;165.#endif166.outunregclass:167.classdestroy(vibdevclass;168.return1;169.170.171.staticintinitS3C6410VIBinit(v

16、oid172.173.intret=-ENODEV;174.p+6?o飞y175.printk(KERNERRAuly:S3C6410VIBinitn;176.ret=GPIOVIBCTLinit(;177.if(ret178.179.printk(KERNERRAuly:S3C6410VIBinit一一Failn;180.returnret;181.182.return0;183.184.staticvoidexitcleanupGPIOVIB(void185.186./x0?uee?187./devfs_unregister_chrdev(Viberator_MAJOR,gpio_vib_

17、ctl;188.#if0189.cdevdel(cdevp;190.unregisterchrdevregion(dev,DEVCOUNT;191.classdestroy(vibdevclass;192.#endif193. device_destroy(vib_dev_class,MKDEV(Viberator_MAJOR,0;194. class_destroy(vib_dev_class;195. unregister_chrdev(Viberator_MAJOR,viberator;196. 197. MODULE_LICENSE(GPL;198. MODULE_DESCRIPTIO

18、N(Peterfirstdriver;199. MODULE_ALIAS_CHARDEV(Viberator_MAJOR,0;200.200. module_init(S3C6410_VIB_init;201. module_exit(cleanup_GPIO_VIB;leddriver.h文件1. ssize_tGPIO_VIB_read(structfile*file,char*buf,size_tcount,loff_t*f_ops;2. ssize_tGPIO_VIB_write(structfile*file,constchar*buf,size_tcount,loff_t*f_op

19、s;3. staticintGPIO_VIB_ioctl(structinode*inode,structfile*file,unsignedintcmd,unsignedlongarg;4. ssize_tGPIO_VIB_open(structinode*inode,structfile*file;5. ssize_tGPIO_VIB_release(structinode*inode,structfile*file;6. staticintGPIO_VIB_CTL_init(void;Kconfig文件1.configLEDTEST2.tristateLEDtestforARMeasy3

20、.defaultn4.help5.thisisaLEDdriverforARMEASYwithS3C6410Makefile文件1.obj-$(CONFIG_LEDTEST+=leddriver.o3、在内核配置里菜单里加入本驱动的配置项达到的效果是，可以通过内核配置来选择是否把本驱动编译进内核里，也就是出现在makemenuconfig后出来的界面里，可以参考9.8章5小负添加新驱动方法1）在arch/arm/Kconfig文件里menuDeviceDrivers与endmenu之间添加1.sourcedrivers/ledtest/Kconfig2）在drivers/Kcconfigmen

21、uDeviceDrivers和endmenu之间添力口1.sourcedrivers/ledtest/Kconfig3修改/drivers/Makefile文件1.Obj-$（CONFIG_LEDTEST+=ledtest/4、编译驱动在kernel目录下，终端输入1.#makemenuconfig“DeviceDrivers下面会看到“LEDtestforARMeasy，选择它，保存并退出1.#make这样，就会在/drivers/ledtest目录下得到leddrivr.ko文件，它就是驱动目标文件，已级编译进了zImage里了，只要用这个kernel烧录到开发板，开机就会自动加载本驱动，

22、PS,如果发现如上编译，没有在ledtest目录下生成leddriver.ko文件，也就是本根没有去编译本驱动，那就把ledtest目录入到/drivers/misc目录下，相应的修改misc下面，然后，在makefile里，不用选直接写成obj-y+=leddriver.o，这样强制的包含进去编译。三、应用程序（测试驱动）用C语言写一个应用，测试上面写的驱动是否工作正常，这是一般的驱动开发流程主要有两个文件：Android.mk和ledtest.c1、在$(YOUR_Android/external/LEDTEST/目录编写ledtest.c文件,ledtest.cledtest.c1.2.

23、#include3.4.#defineDEv:/dev/vib/devicepoint5.LEDON0x116.#define12.nstartgpio_led_drivertestrn13. fd=open(DEVICE_NAME,O_RDWR;14. printf(fd=%dn15. if(fd=-11617.printf(opendevice%serrorn,DEVICENAME1819.21.23.24. /wait1second25. ioctlfd,LED_ON;26. sleep(1;2728.ret=closefd;/closedevice29printf(et=%dn,ret

24、;30.printf(closegpio_ledtestn;3132return0;332、在$(YOUR_Android/external/LEDTEST/目录编写Android.mk文件。这是AndroidMakefile的标准命名，不要更改。Android.mk文件的格式和内容可以参考其他已有的Android.mk文件的写法，针对helloworld程序的Android.mk文件内容如下：.mk12. LOCAL_PATH:=$(callmy-dir3. include$(CLEAR_VARS4. LOCAL_SRC_FILES:=parhelloC5. LOCAL_MODULE:=le

25、dtestapp6. include$(BUILD_EXECUTABLE注意上面IOCAISRCFIIES用来指定源文件：LOCALMODULE指定要编译的模块的名字，下一步骤编译时就要用到：inelude$(BUILD_EXECUTABLE表示要编译成一个可执行文件，如果想编译成动态库则可用BUTID_SHARFDTBRARY,这些可以在$(YOURAndroid/build/core/config.mk杳到。3、回到Android源代码顶层目录进行编译：#cd$(YOUR_Android&makeledtestapp例如我这里的实际操作是#cdAndroid2.1#makeledtesta

26、pp注意makeledtestapp中的目标名ledtestapp就是上面Android.mk文件中由LOCAL_MODULE指定的模块名。编译结果如下makeledtestappPLATFORM_VERSION_CODENAME=RELPLATFORM_VERSION=21-update1TARGET_PRODUCT=genericTARGET_BUILD_VARIANT=engTARGET_SIMULATOR=TARGET_BUILD_TYPE=releaseTARGET_ARCH=armH0ST_ARCH=x86HOST_OS=linuxHOST_BUILD_TYPE=releaseBU

27、ILD_ID=ECLAIR/bin/bash:line0:cd:sdk/layoutopt/app/src/resources:NosuchfileordirectorytargetthumbC:ledtestapp=external/LEDTEST/ledtest.cInstall:out/host/linux-x86/bin/aprioriInstall:out/host/linux-x86/bin/soslimtargetExecutable:ledtestapp(out/target/product/generic/obj/EXECUTABLES/ledtestapp_intermed

28、iates/LINKED/ledtestapptargetNon-prelinked:ledtestapp(out/target/product/generic/symbols/system/bin/ledtestapptargetStrip:ledtestapp(out/target/product/generic/obj/EXECUTABLES/ledtestapp_intermediates/ledtestappInstall:out/target/product/generic/system/lib/libdl.soInstall:out/target/product/generic/

29、system/lib/libc.soInstall:out/target/product/generic/system/lib/libstdc+.soInstall:out/target/product/generic/system/lib/libm.soInstall:out/target/product/generic/system/bin/ledtestapp4、如上面的编译结果所示，编译后的可执行文件存放在out/target/product/generic/system/bin/目录可执行文件是ledtestapp5、拷贝ledtestapp可执行文件到T卡，插入开发板6、开电，在启动进入Android的过程中，串口终端按回车，进入命令行模式7、拷贝可执行文件到根目录#cp/sdcard/ledtestapp/8、执行程序#/ledtestapp通过上面的步骤，可以看到开发板上相应的LED在闭，每秒钟闪一次!