字符设备驱动(一)

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/arch/regs-gpio.h>
#include <asm/hardware.h>

static struct class *firstdrv_class;
static struct class_device *firstdrv_class_dev;

volatile unsigned long *gpfcon=NULL;
volatile unsigned long *gpfdat=NULL;

static int first_drv_open(struct inode *inode,struct file *filp)
{
//printk("fist_drv_open\n");
/*配置GPF4、5、6为输出*/
//清零
*gpfcon &= ~((0x3<<(4*2))|(0x3<<(5*2))|(0x3<<(6*2)));
//设置为输出口
*gpfcon |=((0x1<<(4*2))|(0x1<<(5*2))|(0x1<<(6*2)));

return 0;
}
static ssize_t first_drv_write(struct file *filp,const char __user *buf,size_t count,loff_t *ppos)
{
int val;

copy_from_user(&val,buf,count);//copy_to_user();

if (val==1)
{
//点灯
*gpfdat &=~((1<<4)|(1<<5)|(1<<6));
}
else
{
//灭灯
*gpfdat |=(1<<4)|(1<<5)|(1<<6);
}

//printk("fist_drv_write\n");
return 0;
}
static struct file_operations first_drv_fops={
.owner=THIS_MODULE,
.open=first_drv_open,
.write=first_drv_write,

};

int major;
static int first_drv_init(void)
{
//register_chrdev(111,"first_drv",&first_drv_fops);
// if first args 0, the sysytm auto give the dervice number
major=register_chrdev(0,"first_drv",&first_drv_fops);

firstdrv_class=class_create(THIS_MODULE,"firstdrv");
if(IS_ERR(firstdrv_class))
return PTR_ERR(firstdrv_class);

firstdrv_class_dev=class_device_create(firstdrv_class,NULL,MKDEV(major,0),NULL,"xyz");
if(unlikely(IS_ERR(firstdrv_class_dev)))
return PTR_ERR(firstdrv_class_dev);

/*虚拟地址映射*/
gpfcon=(volatile unsigned long *)ioremap(0x56000050,16);
gpfdat=gpfcon+1;
return 0;

}

static void first_drv_exit(void)
{
unregister_chrdev(major,"first_drv");

class_device_unregister(firstdrv_class_dev);
class_destroy(firstdrv_class);
iounmap(gpfcon);

}
module_init(first_drv_init);
module_exit(first_drv_exit);

MODULE_LICENSE("GPL");