ARM-Linux自动创建设备结点

内核版本：2.6.28

主机平台：Ubuntu 11.04

内核版本：2.6.39

1、首先配置busybox

busybox
Linux System Utilities --->
[*] mdev
[*] Support /etc/mdev.conf
[*] Support command execution at device addition/removal

2、配置内核

3、修改文件系统里的/etc/init.d/rcS

#!/bin/sh
/bin/mount -a
/sbin/ifconfig eth0 192.168.0.3 up
#exec /usr/etc/rc.mouse

4、修改文件系统中/linuxrc文件

#!/bin/sh
#echo "mount /etc as ramfs"
#/bin/mount -n -t ramfs ramfs /etc
#/bin/cp -a /mnt/etc/* /etc

#/bin/mount -n -t ramfs ramfs /var/state/dhcp
#/bin/mount -n -t ramfs ramfs /var/log/boa
#/bin/mount -n -t ramfs ramfs /usr/Setting
#/bin/cp -a /mnt/Setting/* /usr/Setting

#/bin/mount -n -t ramfs ramfs /tmp
#/bin/cp -a /mnt/etc/* /etc

/bin/mount -t proc proc /proc
/bin/mount -t sysfs sysfs /sys
/bin/mount -t tmpfs tmpfs /dev
mkdir /dev/pts
mkdir /dev/shm

/bin/echo /sbin/mdev > /proc/sys/kernel/hotplug
/sbin/mdev -s

exec /sbin/init

4、修改/etcfstab

vi ./etc/fstab
#device mount-point type options dump fsck order
none /dev/pts devpts mode=0622 0 0
tmpfs /dev/shm tmpfs defaults 0 0

这样编写驱动时不用手动创建设备结点文件了

下面是改写的使用混杂设备的ADC驱动程序，这样可以自动创建和删除设备结点了

[cpp]view plaincopy

1. #include
2. #include
4. #include
5. #include/*创建设备节点*/
6. #include
7. #include/*定义DECLARE_WAIT_QUEUE_HEAD*/
8. #include/*定义了irqreturn_t等*/
9. #includeinterrupt.h>/*request_irqdisable_irqenable_irq*/
11. #include
12. #include
13. #include/*其中包含了#include"mach/irqs.h"*/
15. #includeadc.h>
16. #include
18. #defineADC_MAJOR102
19. #defineADC_NAME"my_adc"
20. #defineSUCCESS0
22. staticintadc_open(structinode*,structfile*);
23. staticintadc_release(structinode*,structfile*);
24. staticint__initadc_init(void);
25. staticint__exitadc_exit(void);
26. staticssize_tadc_read(structfile*,char*,size_t,loff_t*);
28. volatileunsignedlongadc_con;
29. unsignedlongadc_dat0;
31. intflag;//等待任务完成标志
33. unsignedlongbuf;//存放转换完成的数据
35. //声明等待队列
36. DECLARE_WAIT_QUEUE_HEAD(adc_wait);
38. structclk*adc_clk;
41. staticirqreturn_tadc_interrupt(intirq,void*dev_id)//中断处理程序
42. {
43. if(flag==0)
44. {
45. buf=(readw(adc_dat0)&0x3ff);//读取转换完成的数据
46. flag=1;
47. wake_up_interruptible(&adc_wait);//唤醒等待其上的进程
48. printk("Readvalueis%ld\n",buf);
49. }
50. returnIRQ_HANDLED;
51. }
53. staticstructfile_operationsadc_ops=
54. {
55. .owner=THIS_MODULE,
56. .read=adc_read,
57. .open=adc_open,
58. .release=adc_release,
59. };
60. staticstructmiscdeviceadc_misc=
61. {
62. .name=ADC_NAME,
63. .minor=ADC_MAJOR,
64. .fops=&adc_ops,
65. };
66. staticint__initadc_init(void)
67. {
68. intret;
69. adc_clk=clk_get(NULL,"adc");//获取时钟
70. clk_enable(adc_clk);//使能时钟
72. ret=misc_register(&adc_misc);//注册设备
73. if(ret<0)
74. {
75. printk("registerdevicefail\n");
76. returnret;
77. }
78. adc_con=(unsignedlong)ioremap(0x58000000,4);
79. adc_dat0=(volatileunsignedlong)ioremap(0x58000000+S3C2410_ADCDAT0,4);
80. if(!(adc_con&adc_dat0))
81. {
82. printk("Failedtoioremap\n");
83. gotohandle;
84. }
85. printk("Initialized...\n");
86. returnSUCCESS;
87. handle:
88. misc_deregister(&adc_misc);
89. return-1;
90. }
92. staticintadc_open(structinode*inode,structfile*file)//打开设备函数
93. {
94. //注册中断
95. intret;
96. //disable_irq(IRQ_ADC);
97. //enable_irq(IRQ_ADC);
98. ret=request_irq(IRQ_ADC,adc_interrupt,IRQF_SHARED,ADC_NAME,1);//注册中断IRQ_ADC在mach/irqs.h中定义
99. if(ret<0)
100. {
101. printk("IRQ%dcannotrequest\n",IRQ_ADC);
102. returnret;
103. }
104. returnSUCCESS;
105. }
107. staticintadc_release(structinode*inode,structfile*file)//关闭设备函数
108. {
109. free_irq(IRQ_ADC,1);//释放中断
110. returnSUCCESS;
111. }
113. staticssize_tadc_read(structfile*file,
114. char*buffer,
115. size_tlength,
116. loff_t*offset)//设备读取函数
117. {
119. writew((1<14)|(0x31<6),adc_con);//设置ADCCON
120. writew((readw(adc_con)|0x1),adc_con);//启动AD转换
121. wait_event_interruptible(adc_wait,flag);
122. flag=0;
123. }
125. staticint__exitadc_exit(void)//驱动卸载函数
126. {
127. iounmap(adc_con);
128. iounmap(adc_dat0);
129. misc_deregister(&adc_misc);
130. clk_disable(adc_clk);
131. clk_put(adc_clk);
132. printk("Theadcisunintialized\n");
133. returnSUCCESS;
134. }
136. module_init(adc_ini