dac712.c

H9200F(内核2.6.12)的DAC接口驱动 操作方法： 1、将驱动程序dac712.ko拷贝到系统目录：/lib/modules 2、执行如下命令加载模块

/***************************************************************
* Beijing Hyesco Embedded System Co.,Ltd.
* www.hyesco.com
* File Name: dac712.c
* Description: DAC driver on Linux for H9200F
* Author:Lijg for at9200F_linux2.6.12 
* Date:  2007-06-26 
* Email: [e-mail]
***************************************************************/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/irq.h> 

#include <asm/arch/AT91RM9200_SYS.h>
#include <asm/arch/hardware.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/string.h>
#include <linux/kdev_t.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/devfs_fs_kernel.h> 

//*********************************************************
//数据类型定义:
//*********************************************************
#define	U32	volatile unsigned int				
#define	U16	volatile unsigned short		
#define	U8	volatile unsigned char

//*********************************************************
//DAC712端口地址结构定义：	 
//*********************************************************
struct  _DA_ADDR 
{
	U16  AT91C_DAC_CH1;     //0x70000060  
}; 


//*********************************************************
//DAC基地址，与硬件电路相关，H9200F的DAC电路包含一个通道，
//地址为：0x7000,0060，由NCS6选择，当用户改变跳线时，基地
//址需要做相应的修改。
//*********************************************************
#define EBI_BASE_ADDRESS	0x70000000L    //DAC712的基地址
#define EBI_OFFSET_ADDRESS	0x60         //DAC712的偏移地址
#define ADDR_sys_offset		EBI_BASE_ADDRESS + EBI_OFFSET_ADDRESS
#define ADDR_Size			0x10              //DAC712的地址空间


//全局变量,常量；
static int major=0;
static char DAC_name[]="DAC712";
struct _DA_ADDR *IO_Addr;
static struct cdev DAC_Devs;
int DA_CH;

//*********************************************************
//函数原型；
//*********************************************************
static int s_open(struct inode * s_node,struct file * s_file);
static int s_write(struct file*s_file, const char*w_buf,int len,loff_t* loff);
static int s_ioctl(struct inode *s_node, struct file *file, unsigned int cmd, unsigned long arg);
static int ADDR_mem(void);

//*********************************************************
//文件操作结构体；
//*********************************************************
struct file_operations fops_DAC=
{
		.owner   =  THIS_MODULE,
		.write   =	(void(*)) s_write,
		.open    =	(void(*)) s_open,
		.ioctl   =	(void(*)) s_ioctl,
 };

/*
 * Set up the cdev structure for a device.
 */
static void DAC_setup_cdev(struct cdev *dev, int minor,
		struct file_operations *fops)
{
	int err, devno = MKDEV(major, minor);
    
	cdev_init(dev, fops);
	dev->owner = THIS_MODULE;
	dev->ops = fops;
	err = cdev_add (dev, devno, 1);
	/* Fail gracefully if need be */
	if (err)
		printk (KERN_NOTICE "Error %d adding DAC_Device%d", err, minor);
}

//*********************************************************
//初始化模块函数；
//*********************************************************
static int ADDR_mem(void)
{		
	
	if(!request_mem_region(ADDR_sys_offset, ADDR_Size,DAC_name)) 
	{
       	printk("request_mem_region 0x70000000L error!\n");
      		return -EBUSY;
	}
	IO_Addr  = ioremap_nocache(ADDR_sys_offset,ADDR_Size);
	if(NULL==IO_Addr)
	{
		printk("ioremap 0x70000000L error!\n");
		release_mem_region(ADDR_sys_offset, ADDR_Size);
    return -EBUSY;
	}
	printk("init IO_ADDR module is ok!\n");
	return 0;	
};

//*********************************************************
//通用延时函数；
//*********************************************************
void Delay(U32 x)
{
	U32 i,j,k;
	for(i=0;i<=x;i++)
		for(j=0;j<2;j++)
			for(k=0;k<2;k++);
}

//*********************************************************
//open函数；
//*********************************************************
static int s_open(struct inode * s_node,struct file * s_file)
{
	    return 0;
}

/*
***********************************************************
** 函数名称:s_ioctl()
** 功能描述:ioctl函数。
***********************************************************
*/
static int s_ioctl(struct inode *s_node, struct file *file, unsigned int cmd, unsigned long arg)
{
	switch(arg)
		{
		case 0:
			DA_CH = 0;	   //选择通道0； 
			break;
		case 1:
			DA_CH = 1;		 //选择通道1； 
			break;
		default:
			break;
		}
	return 0;
}


//*********************************************************
//write函数 ；
//*********************************************************
static int s_write(struct file*s_file, const char *w_buf,int len,loff_t* loff)
{
	 short DA_data;
	
	//从用户空间拷贝数据到内核空间；			
	if(copy_from_user(&DA_data,w_buf,sizeof(short)))	
		return -EFAULT;
	
	switch(DA_CH)
		{
		//选择通道0输出；  
		case 0:
			break;
					
		//选择通道1输出
		case 1:
			IO_Addr->AT91C_DAC_CH1=DA_data;       
			break;  
		}	
	Delay(10);      		
	return 0;
}

//*********************************************************
//初始化模块函数；
//*********************************************************
static int __init s_init_module(void)
{
		int result;
		dev_t dev = MKDEV(major, 0);
		AT91_SYS->PIOC_PDR  |= 0x1000;
  	AT91_SYS->PIOC_ASR  |= 0x1000; 
		AT91_SYS->EBI_SMC2_CSR[6]=0x11003183;
		
		/* Figure out our device number. */
		if (major)
			result = register_chrdev_region(dev, 1, DAC_name);
		else {
			result = alloc_chrdev_region(&dev, 0, 1, DAC_name);
			major = MAJOR(dev);
		}
		if (result < 0) {
			printk(KERN_WARNING "DAC_MODULE_NAME: unable to get major %d\n", major);
			return result;
		}

  	DAC_setup_cdev(&DAC_Devs,0,&fops_DAC);
  	//自动建立设备节点
 		devfs_mk_cdev(MKDEV(major,0),S_IFCHR | S_IRUSR | S_IWUSR | S_IRGRP,"DAC712");
		ADDR_mem();
		
		return 0;
}

//*********************************************************
//清除模块函数；
//*********************************************************
static void __exit s_cleanup_module(void)
{
 	 iounmap((unsigned char *)IO_Addr);
	 release_mem_region(ADDR_sys_offset, ADDR_Size);
	 cdev_del(&DAC_Devs);  
   unregister_chrdev_region(MKDEV(major, 0), 1);	
   printk("<1>IO_ADDR:Good Bye!\n");
	 return;
}

module_init(s_init_module);
module_exit(s_cleanup_module);

MODULE_AUTHOR("chenggp<[e-mail]>");
MODULE_DESCRIPTION("DAC Driver ");
MODULE_LICENSE("GPL");