硬件平臺：FL2440

內核版本：2.6.28

主機平臺：Ubuntu 11.04

內核版本：2.6.39

原創作品，轉載請標明出處 http://blog.csdn.net/yming0221/archive/2011/06/27/6570072.aspx

1、首先配置busybox

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

2、配置內核

3、修改文件系統里的/etc/init.d/rcS

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

4、修改文件系統中/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

這樣編寫驅動時不用手動創建設備結點文件了

下面是改寫的使用混雜設備的ADC驅動程序，這樣可以自動創建和刪除設備結點了

#include <linux/kernel.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/miscdevice.h> /*創建設備節點*/ #include <linux/clk.h> #include <linux/wait.h> /*定義DECLARE_WAIT_QUEUE_HEAD*/ #include <linux/irqreturn.h> /*定義了irqreturn_t等*/ #include <linux/interrupt.h> /*request_irq disable_irq enable_irq*/ #include <asm/io.h> #include <asm/uaccess.h> #include <asm/irq.h> /*其中包含了#include "mach/irqs.h" */ #include <plat/regs-adc.h> #include <mach/regs-clock.h> #define ADC_MAJOR 102 #define ADC_NAME "my_adc" #define SUCCESS 0 static int adc_open(struct inode *,struct file *); static int adc_release(struct inode *,struct file *); static int __init adc_init(void); static int __exit adc_exit(void); static ssize_t adc_read(struct file *,char *,size_t,loff_t *); volatile unsigned long adc_con; unsigned long adc_dat0; int flag;//等待任務完成標志 unsigned long buf;//存放轉換完成的數據 //聲明等待隊列 DECLARE_WAIT_QUEUE_HEAD(adc_wait); struct clk *adc_clk; static irqreturn_t adc_interrupt(int irq,void * dev_id)//中斷處理程序 { if(flag==0) { buf=(readw(adc_dat0) & 0x3ff );//讀取轉換完成的數據 flag=1; wake_up_interruptible(&adc_wait);//喚醒等待其上的進程 printk("Read value is %ld\n",buf); } return IRQ_HANDLED; } static struct file_operations adc_ops = { .owner = THIS_MODULE, .read = adc_read, .open = adc_open, .release = adc_release, }; static struct miscdevice adc_misc = { .name = ADC_NAME, .minor = ADC_MAJOR, .fops = &adc_ops, }; static int __init adc_init(void) { int ret; adc_clk = clk_get(NULL,"adc");//獲取時鐘 clk_enable(adc_clk);//使能時鐘 ret=misc_register(&adc_misc); //注冊設備 if(ret<0) { printk("register device fail\n"); return ret; } adc_con=(unsigned long)ioremap(0x58000000,4); adc_dat0=(volatile unsigned long)ioremap(0x58000000+S3C2410_ADCDAT0,4); if( !(adc_con & adc_dat0) ) { printk("Failed to ioremap\n"); goto handle; } printk("Initialized...\n"); return SUCCESS; handle: misc_deregister(&adc_misc); return -1; } static int adc_open(struct inode * inode,struct file * file) //打開設備函數 { //注冊中斷 int ret; //disable_irq(IRQ_ADC); //enable_irq(IRQ_ADC); ret=request_irq(IRQ_ADC,adc_interrupt,IRQF_SHARED,ADC_NAME,1);//注冊中斷 IRQ_ADC在 mach/irqs.h中定義 if(ret<0) { printk("IRQ %d can not request\n",IRQ_ADC); return ret; } return SUCCESS; } static int adc_release(struct inode * inode,struct file * file) //關閉設備函數 { free_irq(IRQ_ADC,1);//釋放中斷 return SUCCESS; } static ssize_t adc_read(struct file *file, char * buffer, size_t length, loff_t * offset)//設備讀取函數 { writew((1<<14)|(0x31<<6),adc_con); //設置ADCCON writew((readw(adc_con) | 0x1),adc_con); //啟動AD轉換 wait_event_interruptible(adc_wait,flag); flag=0; } static int __exit adc_exit(void) //驅動卸載函數 { iounmap(adc_con); iounmap(adc_dat0); misc_deregister(&adc_misc); clk_disable(adc_clk); clk_put(adc_clk); printk("The adc is unintialized\n"); return SUCCESS; } module_init(adc_init); module_exit(adc_exit); MODULE_LICENSE("GPL");

ARM-Linux自動創建設備結點