ledmod.c

arm9200开发板LED驱动实现

#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 led_major 42


//#include <linux/modversions.h>

MODULE_LICENSE("GPL");

static int led_open(struct inode *,struct file *);
static ssize_t led_read(struct file *,char *,size_t,loff_t *);
static ssize_t led_write(struct file *,const char *,size_t,loff_t *);
static int led_close(struct inode *,struct file *); 


static int led_open(struct inode *inode,struct file *file)
{
 unsigned int *PIO_PER = 0;
 unsigned int *PIO_OER = 0;
 unsigned int *PIO_OWER = 0;
 PIO_PER = ioremap((unsigned long)0xfffff800,(unsigned long)1);  //I/O enable  
 PIO_OER = ioremap((unsigned long)0xfffff810,(unsigned long)1);  //output enable
 PIO_OWER = ioremap((unsigned long)0xfffff8a0,(unsigned long)1); //output write enable
  *PIO_PER=0x40;
  *PIO_OER=0x40;
  *PIO_OWER=0X40;
  return 0;
}

static ssize_t led_read(struct file *file,char *buffer,size_t count,loff_t *offset)
{
 unsigned char *PIO_PDSR = 0;
 unsigned char a=0;
 
 PIO_PDSR = ioremap((unsigned long)0xfffff83c,(unsigned long)1);
 a=readb(PIO_PDSR);
 put_user(a,buffer);
 if((0x40&a)==0)printk(KERN_ALERT "current status is low\n");
 if((a&0x40)==0x40)printk(KERN_ALERT "current status is high\n");
 return (count);
}

static ssize_t led_write(struct file *file,const char *buffer,size_t count,loff_t *offset)
{
unsigned char *PIO_ODSR = 0;
unsigned char value;
PIO_ODSR = ioremap((unsigned long)0xfffff838,(unsigned long)1);	

get_user(value,buffer);
writeb(value,PIO_ODSR);
  return (count);
}

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

struct file_operations led_fops ={
	open:led_open,
	read:led_read,
	write:led_write,
	release:led_close,
};

int led_init(void)
{
	int rc;
	rc=register_chrdev(led_major,"led_device",&led_fops);
	if (rc<0)
	{
		printk(KERN_WARNING "led:can't get major %d\n",led_major);
		return rc;
	}
	printk(KERN_INFO "led:get major %d\n",led_major);
	return 0;
}
	

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

void cleanup_module(void)
{
	unregister_chrdev(led_major,"led_device");
	printk(KERN_ALERT "Goodbye, world\n");
}