xsbase270-数码管驱动笔记

时间：2009-04-06 来源：ruanbanyong1

把字符设备驱动看了个大概，就把板子上的数码管驱动给完成了，一开始驱动的时候没有考虑到延时，数码管点亮的效果总是有问题，加了延时就好了。
下面贴出源码，希望对初学者有帮助。

#include <linux/module.h> //必须包含
#include <linux/init.h> //必须包含
#include <linux/errno.h> //return -XXXXXX
#include <linux/kernel.h> //printk
#include <linux/version.h> // 版本控制
#include <linux/sched.h> //包含很多API
#include <linux/fs.h>    //文件操作
//#include <linux/cdev.h> //struct cdev 这是2.6的产物
#include <asm/uaccess.h> //这里包含了内核空间与用户空间进行数据交换时的函数宏
#include <asm/io.h>     //I/O访问
#include <linux/config.h>
#include <linux/poll.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <asm/arch/xsbase270.h>
#include <asm/hardware.h>

MODULE_LICENSE("GPL");

#define DEVICE_NAME "8lcd"
#define NUM1   0x01
#define NUM2   0x02
#define NUM3   0x03
#define NUM4   0x04
#define NUM5   0x06
//#define SEG_CS1    0x10200000 //A22,a21,a20 = 010->ledcs1
#define SEG_CS2    0x10300000 //a22,a21,a20 = 011->ledcs2
#define SEG_CS3    0x10400000 //            = 100->ledcs3

//unsigned long *cs1_address;
unsigned long *cs2_address;
unsigned long *cs3_address;


static int Emdoor_8Seg_open(struct inode *inode,struct file *filp)
{



     MOD_INC_USE_COUNT; //current module counter add 1;
     return 0;

}

static ssize_t Emdoor_8Seg_write(struct file *file,const char *buffer,size_t count,loff_t *ppos)
{



     return 0;

}

static int Emdoor_8Seg_ioctl(struct inode *ip,struct file *fp,unsigned int cmd,
                 unsigned long arg)
{
     int i;

     int cmd_low;
     int cmd_high;

     cmd_low = cmd & 0x0000ffff;
     cmd_high= cmd & (0xffff0000) >>16;

     writew(cmd_low,cs2_address);
     for(i = 0; i< 10000;i++);
     writew(cmd_high,cs3_address);
     for(i =0 ;i< 10000;i++);

     /*
     switch(cmd)
     {
     case NUM1:
        writew(0x7979,cs2_address);
         for(i = 0; i<10000;i++);
        writew(0x7979,cs3_address);
         for(i = 0; i<10000;i++);
        break;
     case NUM2:
       writew(0x2424,cs2_address);
for(i = 0; i<10000;i++);
       writew(0x2424,cs3_address);
for(i = 0; i<10000;i++);
       break;
     case NUM3:
       writew(0x3030,cs2_address);
        for(i = 0; i<10000;i++);
       writew(0x3030,cs3_address);
        for(i = 0; i<10000;i++);
       break;
     case NUM4:
       writew(0x1919,cs2_address);
        for(i = 0; i<10000;i++);
       writew(0x1919,cs3_address);
        for(i = 0; i<10000;i++);
        break;
     case NUM5:
       writew(0x1212,cs2_address);
        for(i = 0; i<10000;i++);
       writew(0x1212,cs3_address);
for(i = 0; i<10000;i++);
        break;
     default:
    return -EINVAL;


     }

     */


     return 0;


}

static int Emdoor_8Seg_release(struct inode *inode,struct file *filp)
{
     kfree(filp->private_data);
     MOD_DEC_USE_COUNT; //current module counter substract 1
     return 0;


}

static struct file_operations Emdoor_fops={

open:   Emdoor_8Seg_open,            //open operation function
write: Emdoor_8Seg_write,
release: Emdoor_8Seg_release,
ioctl: Emdoor_8Seg_ioctl,

owner: THIS_MODULE,

};


static int __init Emdoor_8Seg_init(void)
{
     int ret;
     int i = 0;

     //    cs1_address = ioremap(SEG_CS1,32); //distribute IO memory map address
      cs2_address = ioremap(SEG_CS2,4);
      cs3_address = ioremap(SEG_CS3,4);


     ret = register_chrdev(61,DEVICE_NAME,&Emdoor_fops);
     if(ret<0)
     {
    printk(DEVICE_NAME "can't get major number\n");
    return ret;

     }
     //驱动加载时候初始化全部显示1
     writew(0x7979,cs2_address);
     for(i = 0; i<10000;i++);

     writew(0x7979,cs3_address);

      for(i = 0; i< 10000;i++);


     return 0;

}

static void __exit Emdoor_8Seg_exit(void)
{
     // iounmap(cs1_address);
      iounmap(cs2_address);
      iounmap(cs3_address);

     unregister_chrdev(61,DEVICE_NAME);//unregister device
}

module_init(Emdoor_8Seg_init);
module_exit(Emdoor_8Seg_exit);

没有什么好说的，实践才是硬道理，下一步驱动按键键盘，。加以！