lm-sensors/prog/detect/i2cdetect.c

/*
    i2cdetect.c - Part of i2cdetect, a user-space program to scan for I2C 
                  devices.
    Copyright (C) 1999-2004  Frodo Looijaard <frodol@dds.nl>,
                             Mark D. Studebaker <mdsxyz123@yahoo.com> and
                             Jean Delvare <khali@linux-fr.org>

    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.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include "i2c-dev.h"
#include "version.h"

#define MODE_AUTO	0
#define MODE_QUICK	1
#define MODE_READ	2

void print_i2c_busses(int);

void help(void)
{
	fprintf(stderr,
	        "Syntax: i2cdetect [-f] [-q|-r] I2CBUS [FIRST LAST]\n"
	        "  I2CBUS is an integer\n"
	        "  With -f, scans all addresses (NOT RECOMMENDED)\n"
	        "  With -q, uses only quick write commands for probing (NOT RECOMMENDED)\n"
	        "  With -r, uses only read byte commands for probing (NOT RECOMMENDED)\n"
	        "  If provided, FIRST and LAST limit the probing range.\n"
	        "  i2cdetect -l lists installed busses only\n");

	print_i2c_busses(0);
}

int open_i2c_dev(const int i2cbus, char *filename)
{
	int file;

	sprintf(filename, "/dev/i2c-%d", i2cbus);
	file = open(filename, O_RDWR);

	if (file >= 0 || errno != ENOENT) {
		return file;
	}

	sprintf(filename, "/dev/i2c/%d", i2cbus);
	file = open(filename, O_RDWR);
	
	return file;
}

int scan_i2c_bus(int file, const int mode, const int first, const int last)
{
	int i, j;
	int res;

	printf("     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f\n");

	for (i = 0; i < 128; i += 16) {
		printf("%02x: ", i);
		for(j = 0; j < 16; j++) {
			/* Skip unwanted addresses */
			if (i+j < first || i+j > last) {
				printf("   ");
				continue;
			}

			/* Set slave address */
			if (ioctl(file, I2C_SLAVE, i+j) < 0) {
				if (errno == EBUSY) {
					printf("UU ");
					continue;
				} else {
					fprintf(stderr,
					        "Error: Could not set address to 0x%02x: %s\n",
					        i+j, strerror(errno));
					return -1;
				}
			}

			/* Probe this address */
			switch (mode) {
			case MODE_QUICK:
				/* This is known to corrupt the Atmel AT24RF08 EEPROM */
				res = i2c_smbus_write_quick(file, I2C_SMBUS_WRITE);
				break;
			case MODE_READ:
				/* This is known to lock SMBus on various write-only chips
				(mainly clock chips) */
				res = i2c_smbus_read_byte(file);
				break;
			default:
				if ((i+j >= 0x30 && i+j <= 0x37)
				 || (i+j >= 0x50 && i+j <= 0x5F))
					res = i2c_smbus_read_byte(file);
				else
					res = i2c_smbus_write_quick(file, I2C_SMBUS_WRITE);
			}

			if (res < 0)
				printf("XX ");
			else
				printf("%02x ", i+j);
		}
		printf("\n");
	}

	return 0;
}

int main(int argc, char *argv[])
{
  char *end;
  int i = 1, i2cbus = -1, file, res;
  char filename[20];
  long funcs;
  int mode = MODE_AUTO;
  int first = 0x03, last = 0x77;
  

  while(i2cbus == -1) {
    if (i >= argc) {
      fprintf(stderr,"Error: No i2c-bus specified!\n");
      help();
      exit(1);
    }

    if(!strcasecmp(argv[i], "-v")) {
      fprintf(stderr,"i2cdetect version %s\n", LM_VERSION);
      exit(0);
    }

    if(!strcmp(argv[i], "-l")) {
      print_i2c_busses(1);
      exit(0);
    }

    if(!strcmp(argv[i], "-f")) {
      first = 0x00;
      last = 0x7F;
      i++;
    } else
    if(!strcmp(argv[i], "-q")) {
      if (mode != MODE_AUTO) {
        fprintf(stderr,"Error: Different modes specified!\n");
        exit(1);
      }
      mode = MODE_QUICK;
      i++;
    } else
    if(!strcmp(argv[i], "-r")) {
      if (mode != MODE_AUTO) {
        fprintf(stderr,"Error: Different modes specified!\n");
        exit(1);
      }
      mode = MODE_READ;
      i++;
    } else {
      i2cbus = strtol(argv[i],&end,0);
      if (*end) {
        fprintf(stderr,"Error: I2CBUS argument not a number!\n");
        help();
        exit(1);
      }
      if ((i2cbus < 0) || (i2cbus > 0xff)) {
        fprintf(stderr,
                "Error: I2CBUS argument out of range (0-255)!\n");
        help();
        exit(1);
      }
      i++;
    }
  }

  /* read address range if present */
  if (i+2 == argc) {
    int tmp;
  
    tmp = strtol(argv[i], &end, 0);
    if (*end) {
      fprintf(stderr,
              "Error: FIRST argment not a number!\n");
      help();
      exit(1);
    }
    if (tmp < first || tmp > last) {
      fprintf(stderr,
              "Error: FIRST argument out of range (0x%02x-0x%02x)!\n",
              first, last);
      help();
      exit(1);
    }
    first = tmp;

    tmp = strtol(argv[i+1], &end, 0);
    if (*end) {
      fprintf(stderr,
              "Error: LAST argment not a number!\n");
      help();
      exit(1);
    }
    if (tmp < first || tmp > last) {
      fprintf(stderr,
              "Error: LAST argument out of range (0x%02x-0x%02x)!\n",
              first, last);
      help();
      exit(1);
    }
    last = tmp;
  } else if (i != argc) {
    help();
    exit(1);
  }

  file = open_i2c_dev(i2cbus, filename);
  if (file < 0) {
    if (errno == ENOENT) {
      fprintf(stderr, "Error: Could not open file `/dev/i2c-%d' or `/dev/i2c/%d': %s\n",
              i2cbus, i2cbus, strerror(ENOENT));
    } else {
      fprintf(stderr, "Error: Could not open file `%s': %s\n",
              filename, strerror(errno));
      if (errno == EACCES)
        fprintf(stderr, "Run as root?\n");
    }
    exit(1);
  }

  if (ioctl(file,I2C_FUNCS,&funcs) < 0) {
    fprintf(stderr,
            "Error: Could not get the adapter functionality matrix: %s\n",
            strerror(errno));
    close(file);
    exit(1);
  }
  if (mode != MODE_READ && !(funcs & I2C_FUNC_SMBUS_QUICK)) {
    fprintf(stderr,
            "Error: Can't use SMBus Quick Write command "
            "on this bus (ISA bus?)\n");
    close(file);
    exit(1);
  }
  if (mode != MODE_QUICK && !(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
    fprintf(stderr,
            "Error: Can't use SMBus Read Byte command "
            "on this bus (ISA bus?)\n");
    close(file);
    exit(1);
  }
  
  fprintf(stderr,"  WARNING! This program can confuse your I2C bus, "
          "cause data loss and worse!\n");
  fprintf(stderr, "  I will probe file %s%s.\n", filename,
          mode==MODE_QUICK?" using quick write commands":
          mode==MODE_READ?" using read byte commands":"");
  fprintf(stderr, "  I will probe address range 0x%02x-0x%02x.\n",
          first, last);
  fprintf(stderr,"  You have five seconds to reconsider and press CTRL-C!\n\n");
  sleep(5);

  res = scan_i2c_bus(file, mode, first, last);

  close(file);

  exit(res?1:0);
}