da_driver.c

DA驱动

#include <linux/module.h> // Needed by all modules
#include <linux/kernel.h> // Needed for KERN_ALERT
#include <linux/init.h>   // Needed for the macros
#include <asm/io.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <sys/syscall.h>
#include <linux/errno.h>
#include <linux/fs.h>

#include <linux/unistd.h>

#include <linux/wrapper.h>
#include <asm/uaccess.h>
#define da_major 152
typedef volatile unsigned int AT91_REG;

//#include <linux/modversions.h>

MODULE_LICENSE("GPL");

static int da_open(struct inode *,struct file *);
static ssize_t da_write(struct file *,const char *,size_t,loff_t *);
static int da_close(struct inode *,struct file *); 


static int da_open(struct inode *inode,struct file *file)
{
	//PIO A基地址ffff f400
	//PIO C基地址ffff f800
	//PMC基地址ffff fc00
  AT91_REG *PIO_PDR=0;   
  AT91_REG *PIO_ASR=0;   
  AT91_REG *PIO_PER=0;   
  AT91_REG *PIO_OWER=0;  
  AT91_REG *PIO_OER=0;   
  AT91_REG *PIO_ODSR=0;  
  AT91_REG *PMC_PCER=0;   
  
      PIO_PDR = ioremap((unsigned long)0xfffff404,(unsigned long)1);
      PIO_ASR = ioremap((unsigned long)0xfffff470,(unsigned long)1);
      PIO_PER = ioremap((unsigned long)0xfffff800,(unsigned long)1);
      PIO_OWER = ioremap((unsigned long)0xfffff8a0,(unsigned long)1);
      PIO_ODSR = ioremap((unsigned long)0xfffff838,(unsigned long)1);
      PIO_OER = ioremap((unsigned long)0xfffff810,(unsigned long)1);
      *PIO_PDR=0X26;//禁止PA1,2,5I/O功能
      *PIO_ASR=0X26;//PA1,2,5选择外围功能A
      *PIO_PER=0x6000;//使能PC14I/O功能，DA的清零信号
      *PIO_OER=0x6000;//PC14输出使能
      *PIO_OWER=0x6000;//PC14输出写使能
      *PIO_ODSR=0x0;//PC14输出0，将DA输出清零
      
      PMC_PCER = ioremap((unsigned long)0xfffffc10,(unsigned long)1);
      *PMC_PCER=0X2000;//使能SPI外围时钟
      *PIO_ODSR=0x6000;//将清零信号置1
 
  return 0;
}



static ssize_t da_write(struct file *file,const char *buffer,size_t count,loff_t *offset)
{ char value;
//SPI define
  AT91_REG *SPI_CR=0;  //SPI控制寄存器，使能SPI
  AT91_REG *SPI_MR=0;  //SPI模式寄存器，设定主机模式，选择NPCS2
  AT91_REG *SPI_TDR=0; //SPI发送数据寄存器
  //AT91_REG *SPI_SR=0;  //SPI状态寄存器，用于检测TDRE
  AT91_REG *SPI_CSR2=0; //SPI片选寄存器，设定数据发送时序
      SPI_CSR2 = ioremap((unsigned long)0xfffe0038,(unsigned long)1);
      SPI_MR = ioremap((unsigned long)0xfffe0004,(unsigned long)1);
      SPI_CR = ioremap((unsigned long)0xfffe0000,(unsigned long)1);
      //SPI_SR = ioremap((unsigned long)0xfffe0010,(unsigned long)1);
      SPI_TDR = ioremap((unsigned long)0xfffe000c,(unsigned long)1);
      *SPI_CSR2=0x30603; //Tcss约33ns，spck约7.4M
      *SPI_MR=0x30001;  //选择NPCS2，主机模式
      *SPI_CR=0x01;     //使能SPI
      while(count>0)
      { get_user(value,buffer++);
        *SPI_TDR=value;
        count--;
      }
      
    
    return (count);  	
}

static int da_close(struct inode *inode,struct file *file)
{
	return 0;
}

struct file_operations da_fops ={
	open:da_open,
	write:da_write,
	release:da_close,
};

int da_init(void)
{
	int rc;
	rc=register_chrdev(da_major,"spi2",&da_fops);
	if (rc<0)
	{
		printk(KERN_WARNING "da:can't get major %d\n",da_major);
		return rc;
	}
	printk(KERN_INFO "da:get major %d\n",da_major);
	return 0;
}
	

int init_module(void)
{
	return da_init();
}

void cleanup_module(void)
{
	unregister_chrdev(da_major,"spi2");
	printk(KERN_ALERT "Goodbye\n");
}