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i2cdetect.c

/*
    i2cdetect.c - 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., 51 Franklin Street, Fifth Floor, Boston,
    MA 02110-1301 USA.
*/

#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/i2c-dev.h>
#include "i2cbusses.h"
#include "../version.h"

#define MODE_AUTO 0
#define MODE_QUICK      1
#define MODE_READ 2
#define MODE_FUNC 3

static void help(void)
{
      fprintf(stderr,
            "Usage: i2cdetect [-y] [-a] [-q|-r] I2CBUS [FIRST LAST]\n"
            "       i2cdetect -F I2CBUS\n"
            "       i2cdetect -l\n"
            "  I2CBUS is an integer or an I2C bus name\n"
            "  If provided, FIRST and LAST limit the probing range.\n");
}

static int scan_i2c_bus(int file, int mode, int first, 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++) {
                  fflush(stdout);

                  /* 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("-- ");
                  else
                        printf("%02x ", i+j);
            }
            printf("\n");
      }

      return 0;
}

struct func
{
      long value;
      const char* name;
};

static const struct func all_func[] = {
      { .value = I2C_FUNC_I2C,
        .name = "I2C" },
      { .value = I2C_FUNC_SMBUS_QUICK,
        .name = "SMBus Quick Command" },
      { .value = I2C_FUNC_SMBUS_WRITE_BYTE,
        .name = "SMBus Send Byte" },
      { .value = I2C_FUNC_SMBUS_READ_BYTE,
        .name = "SMBus Receive Byte" },
      { .value = I2C_FUNC_SMBUS_WRITE_BYTE_DATA,
        .name = "SMBus Write Byte" },
      { .value = I2C_FUNC_SMBUS_READ_BYTE_DATA,
        .name = "SMBus Read Byte" },
      { .value = I2C_FUNC_SMBUS_WRITE_WORD_DATA,
        .name = "SMBus Write Word" },
      { .value = I2C_FUNC_SMBUS_READ_WORD_DATA,
        .name = "SMBus Read Word" },
      { .value = I2C_FUNC_SMBUS_PROC_CALL,
        .name = "SMBus Process Call" },
      { .value = I2C_FUNC_SMBUS_WRITE_BLOCK_DATA,
        .name = "SMBus Block Write" },
      { .value = I2C_FUNC_SMBUS_READ_BLOCK_DATA,
        .name = "SMBus Block Read" },
      { .value = I2C_FUNC_SMBUS_BLOCK_PROC_CALL,
        .name = "SMBus Block Process Call" },
      { .value = I2C_FUNC_SMBUS_PEC,
        .name = "SMBus PEC" },
      { .value = I2C_FUNC_SMBUS_WRITE_I2C_BLOCK,
        .name = "I2C Block Write" },
      { .value = I2C_FUNC_SMBUS_READ_I2C_BLOCK,
        .name = "I2C Block Read" },
      { .value = 0, .name = "" }
};

static void print_functionality(unsigned long funcs)
{
      int i;

      for (i = 0; all_func[i].value; i++) {
            printf("%-32s %s\n", all_func[i].name,
                   (funcs & all_func[i].value) ? "yes" : "no");
      }
}

/*
 * Print the installed i2c busses. The format is those of Linux 2.4's
 * /proc/bus/i2c for historical compatibility reasons.
 */
static void print_i2c_busses(void)
{
      struct i2c_adap *adapters;
      int count;

      adapters = gather_i2c_busses();
      if (adapters == NULL) {
            fprintf(stderr, "Error: Out of memory!\n");
            return;
      }

      for (count = 0; adapters[count].name; count++) {
            printf("i2c-%d\t%-10s\t%-32s\t%s\n",
                  adapters[count].nr, adapters[count].funcs,
                  adapters[count].name, adapters[count].algo);
      }

      free_adapters(adapters);
}

int main(int argc, char *argv[])
{
      char *end;
      int i2cbus, file, res;
      char filename[20];
      unsigned long funcs;
      int mode = MODE_AUTO;
      int first = 0x03, last = 0x77;
      int flags = 0;
      int yes = 0, version = 0, list = 0;

      /* handle (optional) flags first */
      while (1+flags < argc && argv[1+flags][0] == '-') {
            switch (argv[1+flags][1]) {
            case 'V': version = 1; break;
            case 'y': yes = 1; break;
            case 'l': list = 1; break;
            case 'F':
                  if (mode != MODE_AUTO && mode != MODE_FUNC) {
                        fprintf(stderr, "Error: Different modes "
                              "specified!\n");
                        exit(1);
                  }
                  mode = MODE_FUNC;
                  break;
            case 'r':
                  if (mode == MODE_QUICK) {
                        fprintf(stderr, "Error: Different modes "
                              "specified!\n");
                        exit(1);
                  }
                  mode = MODE_READ;
                  break;
            case 'q':
                  if (mode == MODE_READ) {
                        fprintf(stderr, "Error: Different modes "
                              "specified!\n");
                        exit(1);
                  }
                  mode = MODE_QUICK;
                  break;
            case 'a':
                  first = 0x00;
                  last = 0x7F;
                  break;
            default:
                  fprintf(stderr, "Error: Unsupported option "
                        "\"%s\"!\n", argv[1+flags]);
                  help();
                  exit(1);
            }
            flags++;
      }

      if (version) {
            fprintf(stderr, "i2cdetect version %s\n", VERSION);
            exit(0);
      }

      if (list) {
            print_i2c_busses();
            exit(0);
      }

      if (argc < flags + 2) {
            fprintf(stderr, "Error: No i2c-bus specified!\n");
            help();
            exit(1);
      }
      i2cbus = lookup_i2c_bus(argv[flags+1]);
      if (i2cbus < 0) {
            help();
            exit(1);
      }

      /* read address range if present */
      if (argc == flags + 4 && mode != MODE_FUNC) {
            int tmp;

            tmp = strtol(argv[flags+2], &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[flags+3], &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 (argc != flags + 2) {
            help();
            exit(1);
      }

      file = open_i2c_dev(i2cbus, filename, 0);
      if (file < 0) {
            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);
      }

      /* Special case, we only list the implemented functionalities */
      if (mode == MODE_FUNC) {
            close(file);
            printf("Functionalities implemented by %s:\n", filename);
            print_functionality(funcs);
            exit(0);
      }

      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);
      }

      if (!yes) {
            char s[2];

            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, "Continue? [Y/n] ");
            fflush(stderr);
            if (!fgets(s, 2, stdin)
             || (s[0] != '\n' && s[0] != 'y' && s[0] != 'Y')) {
                  fprintf(stderr, "Aborting on user request.\n");
                  exit(0);
            }
      }

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

      close(file);

      exit(res?1:0);
}

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