rs485_driver.c.bak

linux 基于 s3c2440 的rs485驱动及测试程序,可正常收发16Mhz字节数据!

#include <linux/fs.h>
#include <linux/iobuf.h>
//#include <linux/major.h>   
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/smp_lock.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/module.h>
#include <linux/delay.h>
#define RS485DE  	 GPIO_G9     //RED

#define nREV      0
#define nSENT     1
#define RS485SENTBEGIN  1
#define RS485SENTOVER   2
#define LAST_BYTES_FIFO_TO_SHIFTER 2
static int RS485_MAJOR=0;
static devfs_handle_t devfs_handle;
//static struct timer_list rs485_timer;
static int delay_10ms_count;
int    rs485_open(struct inode*, struct file *);
int    rs485_colse(struct inode*, struct file *);
int    rs485_ioctl(struct inode*inode,struct file *flip,unsigned int cmd,unsigned long arg);
//#define DEBUG_WG
#ifdef DEBUG_WG
#define PRIN_DEBUG printk
#else
#define PRIN_DEBUG
#endif

struct rs485de_ctl
{
	long BaudRate;
	int parity;
	int dataBits;
	int stopBits;	
	long count;
};

struct rs485de_ctl *dep;

static struct file_operations gpio_ctl_fops= { 
	ioctl:       rs485_ioctl,
	open:        rs485_open,
	release:     rs485_colse,
};

int __init gpio_init(void) 
{ 
	int result; 
	result = register_chrdev(0, "rs485driver", &gpio_ctl_fops); 
	if (result < 0) { 
		printk("rs485de register error!\n"); 
		return result; 
	} 
	RS485_MAJOR=result;
	devfs_handle = devfs_register(NULL, "rs485driver", DEVFS_FL_DEFAULT,RS485_MAJOR, 0, S_IFCHR | S_IRUSR | S_IWUSR,&gpio_ctl_fops, NULL);
	return 0; 
} 


int gpio_release(struct inode*inode, struct file *filp)
{ 
  devfs_unregister(devfs_handle);
	unregister_chrdev(RS485_MAJOR, "rs485driver"); 
}

int    rs485_open(struct inode*inode, struct file *filp)
{
	 
  set_gpio_ctrl(GPIO_MODE_OUT | RS485DE); 
  set_gpio_pullup(RS485DE);
  write_gpio_bit(GPIO_MODE_OUT | RS485DE,nREV);
	return 0;
}


int    rs485_colse(struct inode*inode, struct file *filp)
{ 
	return 0;
}

void set_rs485de_sent(void)
{
	write_gpio_bit(GPIO_MODE_OUT | RS485DE,nSENT);
	mdelay(1);
}

void set_rs485de_receive(void)
{
	//udelay(9000);
	write_gpio_bit(GPIO_MODE_OUT | RS485DE,nREV);
}


void read_UFSTAT1_and_clr_de()
{
	unsigned int tmp_data,i;
	unsigned int delay_time_us;
	delay_time_us=(1000000/dep->BaudRate)+1;
	delay_time_us=delay_time_us*(dep->parity+dep->stopBits+dep->dataBits)*(LAST_BYTES_FIFO_TO_SHIFTER);
	PRIN_DEBUG("delay time is %dus\n",delay_time_us);	
	for(i=0;i<10;i++)
	{
		tmp_data=UFSTAT1;
		while((tmp_data&0x3f00)!=0)
			{
				udelay(10);
				tmp_data=UFSTAT1;
			}
	}
		for(i=0;i<delay_time_us;i++)
			udelay(1);
	set_rs485de_receive();	
}

int rs485_ioctl(struct inode*inode,struct file *flip,unsigned int cmd,unsigned long arg)
{

	int ret=0;
  switch(cmd)
  {
  	case RS485SENTBEGIN:
  	      set_rs485de_sent();
  	      break;
  	case RS485SENTOVER:
  	      dep=kmalloc(sizeof(*dep),GFP_KERNEL);
  	      copy_from_user(dep,(struct rs485de_ctl *)arg,sizeof(struct rs485de_ctl));
  	      PRIN_DEBUG("baudrate is %d \n",dep->BaudRate);
  	      PRIN_DEBUG("stop is %d \n",dep->stopBits);
  	      PRIN_DEBUG("parity is %d \n",dep->parity);
  	      PRIN_DEBUG("data is %d \n",dep->dataBits);
  	      PRIN_DEBUG("data is %d \n",dep->count);
  	      read_UFSTAT1_and_clr_de();
  	      kfree(dep);
  	      break;
  	default:
  	      ret=-1;
  	      break;
  }      
	return ret;
}

module_init(gpio_init);
module_exit(gpio_release);