Logo Search packages:      
Sourcecode: i2c-tools version File versions  Download package

i2cget.c

/*
    i2cget.c - A user-space program to read an I2C register.
    Copyright (C) 2005       Jean Delvare <khali@linux-fr.org>

    Based on i2cset.c:
    Copyright (C) 2001-2003  Frodo Looijaard <frodol@dds.nl>, and
                             Mark D. Studebaker <mdsxyz123@yahoo.com>
    Copyright (C) 2004-2005  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 "util.h"
#include "i2cbusses.h"
#include <linux/i2c-dev.h>
#include "../version.h"

static void help(void) __attribute__ ((noreturn));

static void help(void)
{
      fprintf(stderr, "Syntax: i2cget [-f] [-y] I2CBUS CHIP-ADDRESS "
              "[DATA-ADDRESS [MODE]]\n"
              "        i2cget -V\n"
              "  MODE can be: 'b' (read byte data, default)\n"
              "               'w' (read word data)\n"
              "               'c' (write byte/read byte)\n"
            "  If DATA-ADDRESS is omitted, a single read byte command is "
            "issued\n"
              "  Append 'p' to MODE for PEC checking\n"
              "  I2CBUS is an integer\n");
      print_i2c_busses(0);
      exit(1);
}

static int check_funcs(int file, int i2cbus, int size, int daddress, int pec)
{
      unsigned long funcs;

      /* check adapter functionality */
      if (ioctl(file, I2C_FUNCS, &funcs) < 0) {
            fprintf(stderr, "Error: Could not get the adapter "
                    "functionality matrix: %s\n", strerror(errno));
            return -1;
      }

      switch (size) {
      case I2C_SMBUS_BYTE:
            if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE)) {
                  fprintf(stderr, "Error: Adapter for i2c bus %d does "
                          "not have read byte capability\n", i2cbus);
                  return -1;
            }
            if (daddress >= 0
             && !(funcs & I2C_FUNC_SMBUS_WRITE_BYTE)) {
                  fprintf(stderr, "Error: Adapter for i2c bus %d does "
                          "not have write byte capability\n", i2cbus);
                  return -1;
            }
            break;

      case I2C_SMBUS_BYTE_DATA:
            if (!(funcs & I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
                  fprintf(stderr, "Error: Adapter for i2c bus %d does "
                          "not have read byte data capability\n", i2cbus);
                  return -1;
            }
            break;

      case I2C_SMBUS_WORD_DATA:
            if (!(funcs & I2C_FUNC_SMBUS_READ_WORD_DATA)) {
                  fprintf(stderr, "Error: Adapter for i2c bus %d does "
                          "not have read word data capability\n", i2cbus);
                  return -1;
            }
            break;
      }

      if (pec
       && !(funcs & (I2C_FUNC_SMBUS_PEC | I2C_FUNC_I2C))) {
            fprintf(stderr, "Warning: Adapter for i2c bus %d does "
                    "not seem to support PEC\n", i2cbus);
      }

      return 0;
}

static int confirm(const char *filename, int address, int size, int daddress,
               int pec)
{
      int dont = 0;

      fprintf(stderr, "WARNING! This program can confuse your I2C "
            "bus, cause data loss and worse!\n");

      /* Don't let the user break his/her EEPROMs */
      if (address >= 0x50 && address <= 0x57 && pec) {
            fprintf(stderr, "STOP! EEPROMs are I2C devices, not "
                  "SMBus devices. Using PEC\non I2C devices may "
                  "result in unexpected results, such as\n"
                  "trashing the contents of EEPROMs. We can't "
                  "let you do that, sorry.\n");
            return 0;
      }

      if (size == I2C_SMBUS_BYTE && daddress >= 0 && pec) {
            fprintf(stderr, "WARNING! All I2C chips and some SMBus chips "
                    "will interpret a write\nbyte command with PEC as a"
                    "write byte data command, effectively writing a\n"
                    "value into a register!\n");
            dont++;
      }

      fprintf(stderr, "I will read from device file %s, chip "
            "address 0x%02x, ", filename, address);
      if (daddress < 0)
            fprintf(stderr, "current data\naddress");
      else
            fprintf(stderr, "data address\n0x%02x", daddress);
      fprintf(stderr, ", using %s.\n",
            size == I2C_SMBUS_BYTE ? (daddress < 0 ?
            "read byte" : "write byte/read byte") :
            size == I2C_SMBUS_BYTE_DATA ? "read byte data" :
            "read word data");
      if (pec)
            fprintf(stderr, "PEC checking enabled.\n");

      fprintf(stderr, "Continue? [%s] ", dont ? "y/N" : "Y/n");
      fflush(stderr);
      if (!user_ack(!dont)) {
            fprintf(stderr, "Aborting on user request.\n");
            return 0;
      }

      return 1;
}

int main(int argc, char *argv[])
{
      char *end;
      int res, i2cbus, address, file;
      int size = I2C_SMBUS_BYTE_DATA;
      int daddress;
      char filename[20];
      int pec = 0;
      int flags = 0;
      int force = 0, yes = 0, version = 0;

      /* handle (optional) flags first */
      while (1+flags < argc && argv[1+flags][0] == '-') {
            switch (argv[1+flags][1]) {
            case 'V': version = 1; break;
            case 'f': force = 1; break;
            case 'y': yes = 1; break;
            default:
                  fprintf(stderr, "Warning: Unsupported flag "
                        "\"-%c\"!\n", argv[1+flags][1]);
                  help();
                  exit(1);
            }
            flags++;
      }

      if (version) {
            fprintf(stderr, "i2cget version %s\n", VERSION);
            exit(0);
      }

      if (argc - flags < 3)
            help();

      i2cbus = strtol(argv[flags+1], &end, 0);
      if (*end || i2cbus < 0 || i2cbus > 0x3f) {
            fprintf(stderr, "Error: I2CBUS argument invalid!\n");
            help();
      }

      address = strtol(argv[flags+2], &end, 0);
      if (*end || address < 3 || address > 0x77) {
            fprintf(stderr, "Error: Chip address invalid!\n");
            help();
      }

      if (!(flags+3 < argc)) {
            size = I2C_SMBUS_BYTE;
            daddress = -1;
      } else {
            daddress = strtol(argv[flags+3], &end, 0);
            if (*end || daddress < 0 || daddress > 0xff) {
                  fprintf(stderr, "Error: Data address invalid!\n");
                  help();
            }
      }

      if (flags+4 < argc) {
            switch (argv[flags+4][0]) {
            case 'b': size = I2C_SMBUS_BYTE_DATA; break;
            case 'w': size = I2C_SMBUS_WORD_DATA; break;
            case 'c': size = I2C_SMBUS_BYTE; break;
            default:
                  fprintf(stderr, "Error: Invalid mode!\n");
                  help();
            }
            pec = argv[flags+4][1] == 'p';
      }

      file = open_i2c_dev(i2cbus, filename, 0);
      if (file < 0
       || check_funcs(file, i2cbus, size, daddress, pec)
       || set_slave_addr(file, address, force))
            exit(1);

      if (!yes && !confirm(filename, address, size, daddress, pec))
            exit(0);

      if (pec && ioctl(file, I2C_PEC, 1) < 0) {
            fprintf(stderr, "Error: Could not set PEC: %s\n",
                    strerror(errno));
            exit(1);
      }

      switch (size) {
      case I2C_SMBUS_BYTE:
            if (daddress >= 0) {
                  res = i2c_smbus_write_byte(file, daddress);
                  if (res < 0)
                        fprintf(stderr, "Warning - write failed\n");
            }
            res = i2c_smbus_read_byte(file);
            break;
      case I2C_SMBUS_WORD_DATA:
            res = i2c_smbus_read_word_data(file, daddress);
            break;
      default: /* I2C_SMBUS_BYTE_DATA */
            res = i2c_smbus_read_byte_data(file, daddress);
      }
      close(file);

      if (res < 0) {
            fprintf(stderr, "Error: Read failed\n");
            exit(2);
      }

      printf("0x%0*x\n", size == I2C_SMBUS_WORD_DATA ? 4 : 2, res);

      exit(0);
}

Generated by  Doxygen 1.6.0   Back to index