#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/types.h>
#include <machine/cpufunc.h>
#include <unistd.h>

void
usage(char *name) {
    fprintf(stderr,
	    "Bad usage\n"
	    "\t%s [-b base] [-d dev] [-t type] adr [data]\n"
	    "\n"
	    "Read/write registers in Winbond SuperIO parts\n"
	    "base is the base address for the chip (default: 0x2e)\n"
	    "dev is the sub-device to talk to (default: -1/global)\n"
	    "type is the chip type (i = ITE, w = WinBond)\n"
	    "adr is the register to read/write\n"
	    "data is the data to write to adr\n", name);
    exit(1);
}

int
main(int argc, char **argv) {
    int	fd, base, dev, type, adr, data, ch;
    char *progname;
    
    type = 'w';
    base = 0x2e;
    dev = -1;
    
    progname = argv[0];
    
    while ((ch = getopt(argc, argv, "b:d:t:")) != -1) {
	switch (ch) {
	    case 'b':
		base = strtol(optarg, NULL, 0) & 0xffff;
		break;
		    
	    case 'd':
		dev =  strtol(optarg, NULL, 0) & 0xff;
		break;

	    case 't':
		if (optarg[0] != 'w' && optarg[0] != 'i') {
		    fprintf(stderr, "type must be w or i\n\n");
		    usage(progname);
		}
		
		type = optarg[0];
		break;

	    default:
		usage(progname);
		break;
	}
    }
    argc -= optind;
    argv += optind;
	
    if (argc != 1 && argc != 2)
	usage(progname);

    if ((fd = open("/dev/io", O_RDWR)) == -1) {
	fprintf(stderr, "Can't open /dev/io: %s\n", strerror(errno));
	exit(1);
    }

    adr = strtol(argv[0], NULL, 0) & 0xff;

    /* Enter extended function mode */
    if (type == 'w') {
	outb(base, 0x87);
	outb(base, 0x87);
    } else {
	/* Taken from the Linux driver drivers/hwmon/it87.c */
	outb(base, 0x87);
	outb(base, 0x01);
	outb(base, 0x55);
	outb(base, 0x55);
    }

    /* Sub device to select (skip if global) */
    if (dev != -1) {
	outb(base, 0x07); /* Logical device select register */
	outb(base + 1, dev & 0xff);
    }
	
    /* Register to access */
    outb(base, adr);
    
    if (argc == 2)	{
	data = strtol(argv[1], NULL, 0) & 0xff;
	printf("Bank 0x%02x: 0x%02x <- 0x%02x\n", dev, adr, data);
	outb(base + 1, data);
    } else
	    printf("Bank 0x%02x: 0x%02x -> 0x%02x\n", dev, adr, inb(base + 1));

    /* Exit extended function mode */
    if (type == 'w') {
	outb(base, 0xaa);
	outb(base, 0xaa);
    } else {
	outb(base, 0x02);
	outb(base, 0x02);
    }

    exit(0);
}