ad_driver.c

AD驱动源码

#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 ad_major 151
typedef volatile unsigned int AT91;

//#include <linux/modversions.h>

MODULE_LICENSE("GPL");

static int ad_open(struct inode *,struct file *);
static ssize_t ad_read(struct file *,char *,size_t,loff_t *);
static ssize_t ad_write(struct file *,const char *,size_t,loff_t *);
static int ad_close(struct inode *,struct file *); 

static  AT91 *SPI_RDR;   //SPI接收数据寄存器
static  AT91 *SPI_SR=0;  //SPI状态寄存器，用于检测TDRE
static  AT91 *SPI_TDR=0; //SPI发送数据寄存器

static char value;   //用于存放控制字

static int ad_open(struct inode *inode,struct file *file)
{
    //PIO A基地址ffff f400
    //PMC基地址ffff fc00
  AT91 *PIO_PDR=0;   
  AT91 *PIO_ASR=0;   
  
  AT91 *PMC_PCER=0;   
  
      PIO_PDR = ioremap((unsigned long)0xfffff404,(unsigned long)1);
      PIO_ASR = ioremap((unsigned long)0xfffff470,(unsigned long)1);
      
      *PIO_PDR=0X27;  //禁止PA0,1,2,5I/O功能
      *PIO_ASR=0X27;  //PA0,1,2,5选择外围功能A
      
      
      PMC_PCER = ioremap((unsigned long)0xfffffc10,(unsigned long)1);
      *PMC_PCER=0X2000;  //使能SPI外围时钟,SPI外围ID为 13
      
 
  return 0;
}



static ssize_t ad_write(struct file *file,const char *buffer,size_t count,loff_t *offset)
{ 
  
  unsigned short int a;

//SPI define，基地址fffe 0000

  AT91 *SPI_CR=0;  //SPI控制寄存器，使能SPI
  AT91 *SPI_MR=0;  //SPI模式寄存器，设定主机模式，选择NPCS2

  AT91 *SPI_CSR1=0; //SPI片选寄存器，设定数据发送时序
      SPI_CSR1 = ioremap((unsigned long)0xfffe0034,(unsigned long)1);
      SPI_MR = ioremap((unsigned long)0xfffe0004,(unsigned long)1);
      SPI_CR = ioremap((unsigned long)0xfffe0000,(unsigned long)1);
      SPI_RDR = ioremap((unsigned long)0xfffe0008,(unsigned long)1); 
      SPI_SR = ioremap((unsigned long)0xfffe0010,(unsigned long)1);
      SPI_TDR = ioremap((unsigned long)0xfffe000c,(unsigned long)1);
      *SPI_CSR1=0xa1281;   //Tcss约110ns，spck约2.4M
      *SPI_MR=0x10001;     //选择NPCS1，主机模式
      *SPI_CR=0x01;        //使能SPI
      a=readw(SPI_RDR);    //读接收寄存器，清除RDRF标志
      get_user(value,buffer);  
      return (count);   
}

static ssize_t ad_read(struct file *file,char *buffer,size_t count,loff_t *offset)
{   unsigned short int b; 
    char a;
      *SPI_TDR=value;   //发送控制字
         while(1)       //等待同步器将转换完成的数据送入SPI_RDR
       { a=readb(SPI_SR);
         if((a&0x01)==0x01)   //若RDRF置1，读SPI_RDR数据
         { b=readw(SPI_RDR);
          break;
         }
       
       } 
    put_user(b,buffer);
    b=b>>8;
    put_user(b,++buffer);
   return(count);
}
 

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

struct file_operations ad_fops ={
    open:ad_open,
    read:ad_read,
    write:ad_write,
    release:ad_close,
};

int ad_init(void)
{
    int rc;
    rc=register_chrdev(ad_major,"spi1",&ad_fops);
    if (rc<0)
    {
        printk(KERN_WARNING "da:can't get major %d\n",ad_major);
        return rc;
    }
    printk(KERN_INFO "da:get major %d\n",ad_major);
    return 0;
}
    

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

void cleanup_module(void)
{
    unregister_chrdev(ad_major,"spi1");
    printk(KERN_ALERT "Goodbye\n");
}