dac0800.c

这是一个芯片DAC0800的驱动程序

/* Note:Your choice is C IDE */
/*
硬件连接说明：	dac0800的数据线接gpa0~gpa7
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>

#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/uaccess.h>
#include <asm/arch/irqs.h>
#include <asm/io.h>
#include <asm/semaphore.h> 
#include <linux/major.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/delay.h>

#define DAC0800_MAJOR 226
#define DAC0800_ADDR 0x08000300

devfs_handle_t dac0800_devfs_dir;
static char dac0800_devices[256];
static unsigned int r_GPDAT,r_GPACON;

int dac0800_open(struct inode *,struct file *);
int dac0800_release(struct inode *,struct file*);

 static ssize_t dac0800_write(struct file*,const char*,size_t,loff_t*);

static struct file_operations dac0800_ctl_fops={
	open:dac0800_open,
	write:dac0800_write,
	release:dac0800_release,
};
int dac0800_open(struct inode *inode,struct file *file)
{
	int minor;
	minor=MINOR(inode->i_rdev);
	printk("open ok\n");
	dac0800_devices[minor]++;
	return 0;
}
static ssize_t dac0800_write(struct file *fp,const char *buf,size_t size,loff_t *ppos)
{
	int val;
	printk("dac0800_write ok\n");
	if(get_user(val,buf))
		return -EFAULT;
	r_GPDAT=(unsigned long)ioremap(0x56000004,4);
	*(volatile unsigned int *)r_GPDAT=val;		
	return 1;
}
int dac0800_release(struct inode *inode,struct file *filp)
{
	int minor;
	minor=MINOR(inode->i_rdev);
	if(dac0800_devices[minor])
		dac0800_devices[minor]--;
	printk("release ok\n");
	return 0;
}

static int __init dac0800_init(void)
{
	r_GPACON=(unsigned long)ioremap(0x56000000,4);
	*(volatile unsigned long *)r_GPACON=0;
	dac0800_devfs_dir=devfs_register(NULL,"dac0800",DEVFS_FL_DEFAULT,DAC0800_MAJOR,0,S_IFCHR|S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP,&dac0800_ctl_fops,NULL);
	printk("dac0800 driver installed ok\n");
	return 0;
}
static void __exit dac0800_exit(void)
{
	devfs_unregister(dac0800_devfs_dir);
	printk("dac0800 driver uninstalled ok\n");
}
module_init(dac0800_init);
module_exit(dac0800_exit);