s3c2440之iic驱动程序编写 程序编写, success, return, result, write

yuyang911220

我的板子用的AT24C08,首先写出驱动的框架：定义 file_operations结构函数static
struct file_operations test_iic =
{



.open = open_iic,

.write = write_iic,

.read = read_iic,
};

加载驱动时的初始化函数和结束时的函数
static
int __init init_iic(void)
{
int ret,result;
   ret = register_chrdev(154,"iic0",&test_iic);

if(ret <
0)

{
        printk("fail!\n");

return ENODEV;

}

else

{printk("iic is success!!!\n");
   result=request_irq(IRQ_IIC,iic_interrupt,IRQF_SHARED,"iic0",iic_interrupt);

if(result <
0)

{
      printk("the interrupt is requested fail\n");

return ENODEV;

}

else

{
       printk("requested success!\n");

return result;

}

return ret;

}
}

static
void __exit exit_iic(void)
{
   unregister_chrdev(154,"iic0");
}
驱动怎么知道调用哪一个呢，要在下面说明一下 ：
module_init(init_iic);
module_exit(exit_iic);

MODULE_LICENSE("GPL");
然后分别实现open，write，read
open函数的实现：
static
int open_iic(struct inode * inode,struct file * file)
{


int cmmd;
    s3c2410_gpio_cfgpin(S3C2410_GPE14,S3C2410_GPE14_IICSCL);
    s3c2410_gpio_cfgpin(S3C2410_GPE15,S3C2410_GPE15_IICSDA);


        IIC_IICCON = ioremap(IICCON,4)
;

        IIC_IICSTAT = ioremap(IICSTAT,4);
        IIC_IICDS = ioremap(IICDS,4);

        IIC_IICADD = ioremap(IICADD,4);
        IIC_IICLC = ioremap(IICLC,4);

        IIC_CLKCON = ioremap(CLKCON,4);

/*打开iic时钟使能*/

*IIC_CLKCON |=(1
<<
16);

     cmmd =
((S3C2410_IICCON_ACKEN)|(S3C2410_IICCON_TXDIV_16)|(S3C2410_IICCON_IRQEN)|(0x0f));
     writel(cmmd,IIC_IICCON);
     writel(0x10,IIC_IICSTAT);
     writel(0x10,IIC_IICADD);



return
0;

}
write函数的实现：
static
int write_iic(struct file*file,const
char __user *userbuf,size_t count,loff_t
*off)
{

int i;
        ack =
0;

if(copy_from_user(wr_data,userbuf,count)!=0)

{
                printk("write is error!!\n");

return EFAULT;

};
        writel(0xa0,IIC_IICDS);
        writel(0xf0,IIC_IICSTAT);


        udelay(100);

while(ack ==
0);
        ack =
0;
        writel(0x00,IIC_IICDS);
        writel(0xaf,IIC_IICCON);
        udelay(100);

while(ack ==
0);
        ack =
0;

for(i=0;i<5;i++)

{
                writel(wr_data[i],IIC_IICDS);
                printk("wr_data=%x\n",wr_data[i]);
                writel(0xaf,IIC_IICCON);
                udelay(100);

while(ack ==
0);
                ack =
0;

}
        writel(0xd0,IIC_IICSTAT);
        writel(0xaf,IIC_IICCON);
        udelay(100);

return count;


}