Android驱动开发实例控制LED灯精.docx

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Android驱动开发实例控制LED灯精.docx

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Android驱动开发实例控制LED灯精.docx

Android驱动开发实例控制LED灯精

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

如上图，通过4个IO口控制这LED，低电平LED亮，

这4个IO口分别是GPM1,GPM2,GPM3,GPM4,

二、驱动程序

1、在kernel文件夹下的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

#mkdirledtest

2、在/driver/ledtest目录下，新建leddriver.c，leddriver.h,Kconfig,Makefile等4个文件

leddriver.c

1.#include

2.#include

3.#include

4.#include /*For__init/__exit/...*/

5.#include

6.#include

7.#include

8.#include

9.#include

10.#include

11.#include

12.#include

13.#include

14.#include

15.#include

16.#include

17.#include//forregister_chrdev（

18.#include

19.#include

20.#include"leddriver.h"

21.#include /*ForMODULE_ALIAS_MISCDEV

22. （WATCHDOG_MINOR*/

23.#include /*Forthewatchdogspecificitems*/

24.#include /*Forfileoperations*/

25.#defineViberator_MAJOR 97 //?

÷éè±?

26.#defineSCULL_NR_DEVS 4

27.#defineSCULL_QUANTUM 4000

28.#defineSCULL_QSET 1000

29.//---doastheGIOdriver

30.#defineDEVCOUNT 4

31.#defineGIO_MINOR 2 /*GIOminorno.*/

32.staticdev_tdev; //éê?

μ?

÷éè±?

33.staticstructcdev*cdev_p;

34.staticintopenCnt;

35.//--è±?

á?

------------

36.intVIB_major =97;//weasigmentitfortest

37.intVIB_minor=0;

38.intVIB_nr_devs=SCULL_NR_DEVS;

39.intVIB_quantum=SCULL_QUANTUM;

40.intVIB_qset=SCULL_QSET;

41.

42.staticstructclass*vib_dev_class;

43.#defineGPNCON S3C64XX_GPNCON

44.#defineGPNDAT S3C64XX_GPNDAT

45.#defineGPNPUD S3C64XX_GPNPUD

46.#defineGPMCONS3C64XX_GPMCON

47.#defineGPMDAT S3C64XX_GPMDAT

48.#defineGPMPUDS3C64XX_GPMPUD

49.

50.#defineVIB_ON0x11

51. #defineVIB_OFF0x22

52.staticconststructfile_operationsGPIO_Viberator_ctl_ops={

53. .owner =THIS_MODULE,

54. .open =GPIO_VIB_open,

55. .read =GPIO_VIB_read,

56. .write =GPIO_VIB_write,

57. .ioctl =GPIO_VIB_ioctl,

58. .release =GPIO_VIB_release,

59.};

60.ssize_tGPIO_VIB_read（structfile*file,char*buf,size_tcount,loff_t*f_ops

61.{

62. printk（"GPIO_VIB_read\r\n";

63. gpio_direction_output（S3C64XX_GPM（3,0;//

64. returncount;

65.}

66.ssize_tGPIO_VIB_write（structfile*file,constchar*buf,size_tcount,loff_t*f_ops

67.{

68. printk（"GPIO_VIB_write\r\n";

69. gpio_direction_output（S3C64XX_GPM（3,1;//

70. returncount;

71.}

72.

73.//ssize_tGPIO_VIB_ioctl（structinode* inode,structfile*file,unsignedintcmd,longdata

74.staticintGPIO_VIB_ioctl（structinode*inode,structfile*file,unsignedintcmd,unsignedlongarg

75.{

76. printk（KERN_ERR"VIB:

GPIO_VIB_ioctl--CMD=%x\n",cmd;

77. switch（cmd

78. {

79. caseVIB_ON:

80. gpio_direction_output（S3C64XX_GPM（1,0;//

81. gpio_direction_output（S3C64XX_GPM（2,0;//

82. gpio_direction_output（S3C64XX_GPM（3,0;//

83. gpio_direction_output（S3C64XX_GPM（4,1;//

84. printk（KERN_ERR"VIB:

GPIO_VIB_ioctl--VIB_ON\n";

85. break;

86. caseVIB_OFF:

87. {

88. printk（KERN_ERR"VIB:

GPIO_VIB_ioctl--VIB_OFF\n";

89. gpio_direction_output（S3C64XX_GPM（1,1;//

90. gpio_direction_output（S3C64XX_GPM（2,1;//

91. gpio_direction_output（S3C64XX_GPM（3,1;//

92. gpio_direction_output（S3C64XX_GPM（4,0;//

93. break;

94. }

95. default:

break;

96.

97. }

98. //gpio_free（S3C64XX_GPN（7;

99.}

100.ssize_tGPIO_VIB_open（structinode*inode,structfile*file

101.{

102.//?

￡?

éêy

103. //MOD_INC_USE_COUNT;

104. printk（"GPIO_VIB_open（\n";

105. return0;

106.}

107.ssize_tGPIO_VIB_release（structinode*inode,structfile*file

108.{

109. //MOD_DEC_USE_COUNT;//?

￡?

éêy?

110. printk（"GPIO_VIB_release（\n";

111. return0;

112.}

113.staticintGPIO_VIB_CTL_init（void

114.{

115. intret =-ENODEV;

116. interror;

117. printk（"----------------------------------------------\r\n";

118. //3?

ê?

ˉú

119. s3c_gpio_cfgpin（S3C64XX_GPM（1,S3C_GPIO_SFN（1;//GPM1output

120. s3c_gpio_cfgpin（S3C64XX_GPM（2,S3C_GPIO_SFN（1;//GPM2output

121. s3c_gpio_cfgpin（S3C64XX_GPM（3,S3C_GPIO_SFN（1;//GPM3output

122. s3c_gpio_cfgpin（S3C64XX_GPM（4,S3C_GPIO_SFN（1;//GPM4output

123.#if1/*?

2ì?

·?

ê?

×￠2á?

ˉ*/

124.ret=register_chrdev（Viberator_MAJOR,"viberator",&GPIO_Viberator_ctl_ops;

125.if（ret<0{

126. printk（KERN_ERR"VIB:

unabletogetmajor%d\n",ret;

127. returnret;

128.}

129.//′′?

¨\uc1class

130.vib_dev_class=class_create（THIS_MODULE,"viberator";

131.if（IS_ERR（vib_dev_class{

132. unregister_chrdev（Viberator_MAJOR,"capi20";

133. returnPTR_ERR（vib_dev_class;

134.}

135.//′′?

¨?

úμ?

￡?

136.device_create（vib_dev_class,NULL,MKDEV（Viberator_MAJOR,0,NULL,"vib";

137.//createapointunder/dev/class/vib

138.//í¨1yéaá?

￡?

ˉ?

ó?

oó￡?

í?

á?

ú/dev/class/éú3é\uc1vib?

úμ?

￡?

ó|ó?

3ìDò?

éò2ù×÷tù2ù×÷?

aúμ?

￡?

í¨1y\uc1open,write,readμèoˉêy2ù×÷￡?

ê?

é?

éò?

′oó?

μ?

ó|ó?

ê?

ày3ìDò?

￡

139. return0;

140.#endif

141.#if0/*×￠2á?

ˉì?

142. if（（error=alloc_chrdev_region（&dev,0,DEVCOUNT,"vibrate"<0

143. {

144. printk（KERN_ERR

145. "VIB:

Couldn'talloc_chrdev_region,error=%d\n",

146. error;

147. return1;

148. }

149. printk（"dev=%d \n",dev;

150. cdev_p=cdev_alloc（;

151. cdev_p->ops=&GPIO_Viberator_ctl_ops;

152. error=cdev_add（cdev_p,dev,DEVCOUNT;

153. if（error{

154. printk（KERN_ERR

155. "VIB:

Couldn'tcdev_add,error=%d\n",error;

156. return1;

157. }

158.

159. vib_dev_class=class_create（THIS_MODULE,"vib-dev";

160. if（IS_ERR（vib_dev_class{

161. res=PTR_ERR（vib_dev_class;

162. gotoout_unreg_class;

163. }

164. return0;

165.#endif

166.out_unreg_class:

167. class_destroy（vib_dev_class;

168.return1;

169.}

170.

171.staticint__initS3C6410_VIB_init（void

172.{

173. intret=-ENODEV;

174. //μ÷ó?

oˉêy

175. printk（KERN_ERR"Auly:

S3C6410_VIB_init---\n";

176. ret=GPIO_VIB_CTL_init（;

177. if（ret

178. {

179. printk（KERN_ERR"Auly:

S3C6410_VIB_init--Fail\n";

180. returnret;

181. }

182. return0;

183.}

184.staticvoid__exitcleanup_GPIO_VIB（void

185.{

186. //×￠?

úéè±?

187. // devfs_unregister_chrdev（Viberator_MAJOR,"gpio_vib_ctl";

188.#if0

189. cdev_del（cdev_p;

190. unregister_chrdev_region（dev,DEVCOUNT;

191. class_destroy（vib_dev_class;

192.#endif

193.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_DESCRIPTION（"Peterfirstdriver";

199.MODULE_ALIAS_CHARDEV（Viberator_MAJOR,0;

200.

201.module_init（S3C6410_VIB_init;

202.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_ops;

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.configLEDTEST

2. tristate"LEDtestforARMeasy"

3. defaultn

4. help

5. thisisaLEDdriverforARMEASYwithS3C6410

Makefile文件

1.obj-$（CONFIG_LEDTEST+=leddriver.o

3、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

1）在arch/arm/Kconfig文件里menu"DeviceDrivers"与endmenu之间添加

1.source"drivers/ledtest/Kconfig"

2）在drivers/Kconfigmenu"DeviceDrivers"和endmenu之间添加

1.source"drivers/ledtest/Kconfig"

3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，

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.c

1、

在$（YOUR_Android/external/LEDTEST/目录编写ledtest.c文件，

ledtest.c

1.#include

2.#include

3.#include//contacttheopen（,close（,read（,write（andsoon!

4.#define"/dev/vib"//devicepoint

5.#defineLED_ON 0x11

6.#define

7.intmain（intargc,char**argv

9. intfd;

10.int

11. char*i;

12."\nstartgpio_led_drivertest\r\n"

13. fd=open（DEVICE_NAME,O_RDWR;//Opendevice,getthehandle

14."fd=%d\n"

15. if（fd==-1//openfail

16.

17. printf（"opendevice%serror\n",DEVICE_NAME;

18.

19. else

20.

21. while（1

22.

23. ioctl（fd,LED_OFF;//calltheoutputfunctiontooffLEDs

24.//wait1second

25. ioctl（fd,LED_ON;

26. sleep（1

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