lcdcls.c - clear the LCD character display on OpenBSD/luna88k

lcdcls.c

/*
 * Copyright (c) 2013 Kenji Aoyama
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define LCD	"/dev/lcd"

#include <sys/ioctl.h>
#include <machine/lcd.h>

#include <fcntl.h>
#include <stdio.h>

/* Prototype */
void usage(void);

/*
 * Clear the LCD on OpenBSD/luna88k.
 * Restore boot time message if -r flag is specified.
 */

int
main(int argc, char *argv[])
{
	int fd, ret, rflag = 0, val;
	char ch;

	while ((ch = getopt(argc, argv, "hr")) != -1)
		switch (ch) {
		case 'h':
			usage();
			break;
		case 'r':
			rflag = 1;
			break;
		}

	if ((fd = open(LCD, O_WRONLY)) == -1) {
		perror("open");
		exit(1);
	}

	val = LCDCLS;
	if (rflag) val = LCDRESTORE;

	if ((ret =ioctl(fd, val)) == -1) {
		perror("ioctl");
		exit(1);
	}

	close(fd);
	exit(0);
}

void
usage(void) {
	extern char *__progname;

	fprintf(stderr, "usage: %s [-r]\n", __progname);
	exit(1);
}

After clearing the LCD character display with this tool, you can put your favorite message on the LCD by:

# echo "foo" > /dev/lcd