/*
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>
Copyright (C) 2008-2012 Jean Delvare <jdelvare@suse.de>
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.
*/
/* For strdup and snprintf */
#define _BSD_SOURCE 1 /* for glibc <= 2.19 */
#define _DEFAULT_SOURCE 1 /* for glibc >= 2.19 */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h> /* for NAME_MAX */
#include <sys/ioctl.h>
#include <string.h>
#include <strings.h> /* for strcasecmp() */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <dirent.h>
#include <fcntl.h>
#include <errno.h>
#include "i2cbusses.h"
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
enum adt { adt_dummy, adt_isa, adt_i2c, adt_smbus, adt_unknown };
struct adap_type {
const char *funcs;
const char* algo;
};
static struct adap_type adap_types[5] = {
{ .funcs = "dummy",
.algo = "Dummy bus", },
{ .funcs = "isa",
.algo = "ISA bus", },
{ .funcs = "i2c",
.algo = "I2C adapter", },
{ .funcs = "smbus",
.algo = "SMBus adapter", },
{ .funcs = "unknown",
.algo = "N/A", },
};
static enum adt i2c_get_funcs(int i2cbus)
{
unsigned long funcs;
int file;
char filename[20];
enum adt ret;
file = open_i2c_dev(i2cbus, filename, sizeof(filename), 1);
if (file < 0)
return adt_unknown;
if (ioctl(file, I2C_FUNCS, &funcs) < 0)
ret = adt_unknown;
else if (funcs & I2C_FUNC_I2C)
ret = adt_i2c;
else if (funcs & (I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA))
ret = adt_smbus;
else
ret = adt_dummy;
close(file);
return ret;
}
/* Remove trailing spaces from a string
Return the new string length including the trailing NUL */
static int rtrim(char *s)
{
int i;
for (i = strlen(s) - 1; i >= 0 && (s[i] == ' ' || s[i] == '\n'); i--)
s[i] = '\0';
return i + 2;
}
void free_adapters(struct i2c_adap *adapters)
{
int i;
for (i = 0; adapters[i].name; i++)
free(adapters[i].name);
free(adapters);
}
/* We allocate space for the adapters in bunches. The last item is a
terminator, so here we start with room for 7 adapters, which should
be enough in most cases. If not, we allocate more later as needed. */
#define BUNCH 8
/* n must match the size of adapters at calling time */
static struct i2c_adap *more_adapters(struct i2c_adap *adapters, int n)
{
struct i2c_adap *new_adapters;
new_adapters = realloc(adapters, (n + BUNCH) * sizeof(struct i2c_adap));
if (!new_adapters) {
free_adapters(adapters);
return NULL;
}
memset(new_adapters + n, 0, BUNCH * sizeof(struct i2c_adap));
return new_adapters;
}
struct i2c_adap *gather_i2c_busses(void)
{
char s[120];
struct dirent *de, *dde;
DIR *dir, *ddir;
FILE *f;
char fstype[NAME_MAX], sysfs[NAME_MAX], n[NAME_MAX];
int foundsysfs = 0;
int count=0;
struct i2c_adap *adapters;
adapters = calloc(BUNCH, sizeof(struct i2c_adap));
if (!adapters)
return NULL;
/* look in /proc/bus/i2c */
if ((f = fopen("/proc/bus/i2c", "r"))) {
while (fgets(s, 120, f)) {
char *algo, *name, *type, *all;
int len_algo, len_name, len_type;
int i2cbus;
algo = strrchr(s, '\t');
*(algo++) = '\0';
len_algo = rtrim(algo);
name = strrchr(s, '\t');
*(name++) = '\0';
len_name = rtrim(name);
type = strrchr(s, '\t');
*(type++) = '\0';
len_type = rtrim(type);
sscanf(s, "i2c-%d", &i2cbus);
if ((count + 1) % BUNCH == 0) {
/* We need more space */
adapters = more_adapters(adapters, count + 1);
if (!adapters)
return NULL;
}
all = malloc(len_name + len_type + len_algo);
if (all == NULL) {
free_adapters(adapters);
return NULL;
}
adapters[count].nr = i2cbus;
adapters[count].name = strcpy(all, name);
adapters[count].funcs = strcpy(all + len_name, type);
adapters[count].algo = strcpy(all + len_name + len_type,
algo);
count++;
}
fclose(f);
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", 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) {
int i2cbus;
enum adt type;
char *px;
px = fgets(s, 120, f);
fclose(f);
if (!px) {
fprintf(stderr, "%s: read error\n", n);
continue;
}
if ((px = strchr(s, '\n')) != NULL)
*px = 0;
if (!sscanf(de->d_name, "i2c-%d", &i2cbus))
continue;
if (!strncmp(s, "ISA ", 4)) {
type = adt_isa;
} else {
/* Attempt to probe for adapter capabilities */
type = i2c_get_funcs(i2cbus);
}
if ((count + 1) % BUNCH == 0) {
/* We need more space */
adapters = more_adapters(adapters, count + 1);
if (!adapters)
return NULL;
}
adapters[count].nr = i2cbus;
adapters[count].name = strdup(s);
if (adapters[count].name == NULL) {
free_adapters(adapters);
return NULL;
}
adapters[count].funcs = adap_types[type].funcs;
adapters[count].algo = adap_types[type].algo;
count++;
}
}
closedir(dir);
done:
return adapters;
}
static int lookup_i2c_bus_by_name(const char *bus_name)
{
struct i2c_adap *adapters;
int i, i2cbus = -1;
adapters = gather_i2c_busses();
if (adapters == NULL) {
fprintf(stderr, "Error: Out of memory!\n");
return -3;
}
/* Walk the list of i2c busses, looking for the one with the
right name */
for (i = 0; adapters[i].name; i++) {
if (strcmp(adapters[i].name, bus_name) == 0) {
if (i2cbus >= 0) {
fprintf(stderr,
"Error: I2C bus name is not unique!\n");
i2cbus = -4;
goto done;
}
i2cbus = adapters[i].nr;
}
}
if (i2cbus == -1)
fprintf(stderr, "Error: I2C bus name doesn't match any "
"bus present!\n");
done:
free_adapters(adapters);
return i2cbus;
}
/*
* Parse an I2CBUS command line argument and return the corresponding
* bus number, or a negative value if the bus is invalid.
*/
int lookup_i2c_bus(const char *i2cbus_arg)
{
unsigned long i2cbus;
char *end;
i2cbus = strtoul(i2cbus_arg, &end, 0);
if (*end || !*i2cbus_arg) {
/* Not a number, maybe a name? */
return lookup_i2c_bus_by_name(i2cbus_arg);
}
if (i2cbus > 0xFFFFF) {
fprintf(stderr, "Error: I2C bus out of range!\n");
return -2;
}
return i2cbus;
}
/*
* Parse a CHIP-ADDRESS command line argument and return the corresponding
* chip address, or a negative value if the address is invalid.
*/
int parse_i2c_address(const char *address_arg)
{
long address;
char *end;
address = strtol(address_arg, &end, 0);
if (*end || !*address_arg) {
fprintf(stderr, "Error: Chip address is not a number!\n");
return -1;
}
if (address < 0x03 || address > 0x77) {
fprintf(stderr, "Error: Chip address out of range "
"(0x03-0x77)!\n");
return -2;
}
return address;
}
int open_i2c_dev(int i2cbus, char *filename, size_t size, int quiet)
{
int file;
snprintf(filename, size, "/dev/i2c/%d", i2cbus);
filename[size - 1] = '\0';
file = open(filename, O_RDWR);
if (file < 0 && (errno == ENOENT || errno == ENOTDIR)) {
sprintf(filename, "/dev/i2c-%d", i2cbus);
file = open(filename, O_RDWR);
}
if (file < 0 && !quiet) {
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;
}
int set_slave_addr(int file, int address, int force)
{
/* With force, let the user read from/write to the registers
even when a driver is also running */
if (ioctl(file, force ? I2C_SLAVE_FORCE : I2C_SLAVE, address) < 0) {
fprintf(stderr,
"Error: Could not set address to 0x%02x: %s\n",
address, strerror(errno));
return -errno;
}
return 0;
}