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Script/i2c-tools-3.1.0/tools/i2cbusses.c

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+/*
+    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) 2008-2010  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.
+*/
+
+/* For strdup and snprintf */
+#define _BSD_SOURCE 1
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/param.h>	/* for NAME_MAX */
+#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-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;
+}