#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <dev/ppbus/ppi.h>
#include <dev/ppbus/ppbconf.h>


/*
Ripped off from http://excamera.com/articles/21/parallel.html, modified 18/7/05 wharrop
(check the licence of ripped off code before including this in any products)

/dev/ppi0 must be r/w'able by the user who runs this program

This program take a command line int, and "pushes the power button" for that length of time.
(if you have the right hardware)

*/

static int ppi_fd;

static void init(void)
{
	char port[] = "/dev/ppi0";

	ppi_fd = open(port, O_RDWR);
	if (ppi_fd < 0) {
		perror(port);
		exit(1);
	}
}

static void deinit(void)
{
	close(ppi_fd);
}

static void do_out(uint8_t outval, useconds_t delay_us)
{
	uint8_t tmp;

	/* put our data on the line */
	ioctl(ppi_fd, PPISDATA, &outval);

	/* get ctrl register */
	ioctl(ppi_fd, PPIGCTRL, &tmp);

	/* set strobe */
	tmp |= STROBE;
	ioctl(ppi_fd, PPISCTRL, &tmp);

	/* sleep with strobe held */
	usleep(delay_us);

	/* unset strobe */
	tmp &= ~STROBE;
	ioctl(ppi_fd, PPISCTRL, &tmp);

	/* set data to 0 */
	ioctl(ppi_fd, PPISDATA, 0x00);
}

void
usage(const char *name)
{
	printf("\nUsage: %s <pin> [delay]\n\n", name);
	printf("  <pin> - select the data pin (0 through 7) to operate on\n");
	printf("  [delay] - optional delay (in fractional seconds) to wait before clearing output (default = 1s)\n\n");
	exit(1);
}

int
main(int argc, char *argv[])
{
	float delay_s;
	int pin, delay_us;

        switch (argc) {
                case 2:
			pin = strtol(argv[1], NULL, 0);
			delay_s = 1.0;
			break;
                case 3:
			pin = strtol(argv[1], NULL, 0);
			delay_s = strtof(argv[2], NULL);
			break;
                default:
			usage(argv[0]);
			break;
        }

	if (pin < 0 || pin > 7)
		usage(argv[0]);

	delay_us = (int)(delay_s * 1000000);

	if (delay_us < 0)
		usage(argv[0]);

	init();
	printf("Sending 0x%02x to parallel port for %0.3fs\n", 0xFF & (1 << pin), delay_s);
	do_out(0xFF & (1 << pin), delay_us);
	deinit();

	return 0;
}