root/lm-sensors/trunk/prog/dump/i2cbusses.c @ 2675

/*
    i2cbusses: Print the installed i2c busses for both 2.4 and 2.6 kernels.
               Part of user-space programs to access for I2C 
               devices.
    Copyright (c) 1999-2003  Frodo Looijaard <frodol@dds.nl> and
                             Mark D. Studebaker <mdsxyz123@yahoo.com>

    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 <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <stdio.h>
#include <limits.h>
#include <dirent.h>
#include <fcntl.h>
#include <errno.h>
#include "i2cbusses.h"

/*
   this just prints out the installed i2c busses in a consistent format, whether
   on a 2.4 kernel using /proc or a 2.6 kernel using /sys.
   If procfmt == 1, print out exactly /proc/bus/i2c format on stdout.
   This allows this to be used in a program to emulate /proc/bus/i2c on a
   sysfs system.
*/
void print_i2c_busses(int procfmt)
{
        FILE *fptr;
        char s[100];
        struct dirent *de, *dde;
        DIR *dir, *ddir;
        FILE *f;
        char *border;
        char dev[NAME_MAX], fstype[NAME_MAX], sysfs[NAME_MAX], n[NAME_MAX];
        int foundsysfs = 0;
        int tmp;
        int count=0;


        /* look in /proc/bus/i2c */
        if((fptr = fopen("/proc/bus/i2c", "r"))) {
                while(fgets(s, 100, fptr)) {
                        if(count++ == 0 && !procfmt)
                                fprintf(stderr,"  Installed I2C busses:\n");
                        if(procfmt)
                                printf("%s", s);        
                        else
                                fprintf(stderr, "    %s", s);   
                }
                fclose(fptr);
                goto done;
        }

        /* look in sysfs */
        /* First figure out where sysfs was mounted */
        if ((f = fopen("/proc/mounts", "r")) == NULL) {
                goto done;
        }
        while (fgets(n, NAME_MAX, f)) {
                sscanf(n, "%[^ ] %[^ ] %[^ ] %*s\n", dev, sysfs, fstype);
                if (strcasecmp(fstype, "sysfs") == 0) {
                        foundsysfs++;
                        break;
                }
        }
        fclose(f);
        if (! foundsysfs) {
                goto done;
        }

        /* Bus numbers in i2c-adapter don't necessarily match those in
           i2c-dev and what we really care about are the i2c-dev numbers.
           Unfortunately the names are harder to get in i2c-dev */
        strcat(sysfs, "/class/i2c-dev");
        if(!(dir = opendir(sysfs)))
                goto done;
        /* go through the busses */
        while ((de = readdir(dir)) != NULL) {
                if (!strcmp(de->d_name, "."))
                        continue;
                if (!strcmp(de->d_name, ".."))
                        continue;

                /* this should work for kernels 2.6.5 or higher and */
                /* is preferred because is unambiguous */
                sprintf(n, "%s/%s/name", sysfs, de->d_name);
                f = fopen(n, "r");
                /* this seems to work for ISA */
                if(f == NULL) {
                        sprintf(n, "%s/%s/device/name", sysfs, de->d_name);
                        f = fopen(n, "r");
                }
                /* non-ISA is much harder */
                /* and this won't find the correct bus name if a driver
                   has more than one bus */
                if(f == NULL) {
                        sprintf(n, "%s/%s/device", sysfs, de->d_name);
                        if(!(ddir = opendir(n)))
                                continue;               
                        while ((dde = readdir(ddir)) != NULL) {
                                if (!strcmp(dde->d_name, "."))
                                        continue;
                                if (!strcmp(dde->d_name, ".."))
                                        continue;
                                if ((!strncmp(dde->d_name, "i2c-", 4))) {
                                        sprintf(n, "%s/%s/device/%s/name",
                                                sysfs, de->d_name, dde->d_name);
                                        if((f = fopen(n, "r")))
                                                goto found;
                                }
                        }
                }

found:
                if (f != NULL) {
                        char    x[120];

                        fgets(x, 120, f);
                        fclose(f);
                        if((border = index(x, '\n')) != NULL)
                                *border = 0;
                        if(count++ == 0 && !procfmt)
                                fprintf(stderr,"  Installed I2C busses:\n");
                        /* match 2.4 /proc/bus/i2c format as closely as possible */
                        if(!strncmp(x, "ISA ", 4)) {
                                if(procfmt)
                                        printf("%s\t%-10s\t%-32s\t%s\n", de->d_name,
                                                "dummy", x, "ISA bus algorithm");
                                else
                                        fprintf(stderr, "    %s\t%-10s\t%-32s\t%s\n", de->d_name,
                                                "dummy", x, "ISA bus algorithm");
                        } else if(!sscanf(de->d_name, "i2c-%d", &tmp)) {
                                if(procfmt)
                                        printf("%s\t%-10s\t%-32s\t%s\n", de->d_name,
                                                "dummy", x, "Dummy bus algorithm");
                                else
                                        fprintf(stderr, "    %s\t%-10s\t%-32s\t%s\n", de->d_name,
                                                "dummy", x, "Dummy bus algorithm");
                        } else {
                                if(procfmt)
                                        printf("%s\t%-10s\t%-32s\t%s\n", de->d_name,
                                                "unknown", x, "Algorithm unavailable");
                                else
                                        fprintf(stderr, "    %s\t%-10s\t%-32s\t%s\n", de->d_name,
                                                "unknown", x, "Algorithm unavailable");
                        }
                }
        }
        closedir(dir);

done:
        if(count == 0 && !procfmt)
                fprintf(stderr,"Error: No I2C busses found!\n"
                               "Be sure you have done 'modprobe i2c-dev'\n"
                               "and also modprobed your i2c bus drivers\n");
}

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

        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");
                }
        }
        
        return file;
}