ppdev.c

at51系列单片机编程源码

/* ----------------------------------------------------------------------------
 * ppdev.c
 * this module contains all functions cope with the parallel port
 *
 * Copyright 2003/2004
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 * ----------------------------------------------------------------------------*/
#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/ppdev.h>
#include "isp-at89.h"

/* Parallel port stuff */

/* This function takes the given parportdevice, checks if
   is a valid character device and if so, claim it.
   It returns a filehandle on success, otherwise ERROR. */
int
parport_gethandle (char *ppdev)
{
	int rc = ERROR;

#ifndef __powerpc__
	if (getFileStatus(ppdev) == FST_CHARDEV) {
		if((rc = parport_claim (ppdev)) == ERROR)
			printf (_("-- ERROR: Couldn't claim parport device [%s]\n"), ppdev);
	} else
		printf (_("-- ERROR: Have problems accessing parport device [%s]: %s\n"), ppdev, strerror(errno));
#else
	rc = 0xAA55;  /* random value */
#endif
	return rc;
}

/* open /dev/parportX device and claim it.
 * The return value is a file descriptor or -1
 * in case of error.
 */
int
parport_claim(char *dev)
{
	int fd, rc = ERROR;
	long dummy = 0;

	if ((fd = open(dev, O_RDWR )) > 0) {
		if ((ioctl (fd, PPCLAIM, &dummy)) != 0) {
			close (fd);
		} else {
			ioctl (fd, PPWDATA, &dummy);   /* clear parport */
			rc = fd;
		}
	}
	return rc;
}

void
parport_release (int fd)
{
#ifndef __powerpc__
	long dummy = 0;
	ioctl (fd, PPWDATA, &dummy);   /* clear parport */
	ioctl (fd, PPRELEASE, &dummy);
	close (fd);
#endif
}

unsigned char
parport_wdata (int fd, unsigned char wdata)
{
	unsigned char rdata = 0;
	ioctl (fd, PPWDATA, &wdata);
	ioctl (fd, PPRSTATUS, &rdata);
#ifdef DEBUG
	debug_adddata (wdata, rdata);
#endif
	return ((rdata >> MISO_BIT) & 1);     /* return atmel's reaction */
}