/*
 * Copyright (c) 2015  Sulev-Madis Silber <ketas@si.pri.ee>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *
 * ORIGINAL CODE:
 *
 * i2cscan  FreeBSD version of i2cdetect
 *
 *          Compile with:
 *              cc i2cscan.c -o i2cscan
 *
 * Winston Smith <smith.winston.101@gmail.com>
 */


#include <sys/cdefs.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <unistd.h>
#include <dev/iicbus/iic.h>


/*
 * Scan for the specified slave by trying to read a byte
 */

int scan(int fd, int slave)
{
	uint8_t              buf[2] = { 0, 0 };
	uint16_t             offset = 0;
	struct iic_msg       msg[2];
	struct iic_rdwr_data rdwr;
	
	
	slave = slave << 1;
	
	
	msg[0].slave = slave;
	msg[0].flags = !IIC_M_RD;
	msg[0].len   = sizeof(offset);
	msg[0].buf   = (uint8_t*)&offset;
	
	msg[1].slave = slave;
	msg[1].flags = IIC_M_RD;
	msg[1].len   = sizeof(buf);
	msg[1].buf   = buf;
	
	
	rdwr.nmsgs = 2;
	rdwr.msgs  = msg;
	
	if (ioctl(fd, I2CRDWR, &rdwr) < 0)
	{
		switch (errno)
		{
			case ENXIO:
				// Doesn't exist
				return 1;
			case EBUSY:
				// Currently in use
				return 2;
			default:
				perror("ioctl(I2CRDWR) failed");
				return -1;
		}
	}
	
	return 0;
}


int main(int argc, char **argv)
{
	int c, r, fd, addr;
	char* dev = "/dev/iic0";
	
	
	if (argc > 1)
	{
		dev = argv[1];
	}
	
	if ((fd = open(dev, O_RDWR)) < 0)
	{
		perror("open failed");
		exit(-1);
	}
	
	printf("Checking device: %s\n", dev);
	printf("Scan using 8-bit addresses, display using 7-bit addresses\n");
	printf("   00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F\n");
	
	for (r = 0; r < 8; r++)
	{
		printf("%02X", r * 16);
		
		for (c = 0; c < 16; c++)
		{
			addr = (r * 16) + c;
			
			switch (scan(fd, addr))
			{
				case 0:
					printf(" %02X", addr);
					break;
				case 1:
					printf(" --");
					break;
				case 2:
					printf(" UU");
					break;
				default:
					break;
			}
		}
		
		printf("\n");
	}
	
	close(fd);
	exit(0);
}