[PATCH 0/3] i2c-tools: Allow passing i2c bus by name

[PATCH 0/3] i2c-tools: Allow passing i2c bus by name

[Jean Delvare]

Hi all,

This patch set lets the user provide the i2c bus by name, rather than
number, in i2cdetect, i2cdump, i2cget and i2cset. The first patch
refactors the handling of the i2cbus command line argument so that
further changes only have to be done in once place. The second patch
splits print_i2c_busses into a gathering part and a printing part. The
third patch makes use of the gathering part to resolve the bus name to
a bus number.

This has been tested on both Linux 2.4 and Linux 2.6 and works well for
me. I welcome comments, reviews and testing.

Thanks,
-- 
Jean Delvare

_______________________________________________
i2c mailing list
i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org
http://lists.lm-sensors.org/mailman/listinfo/i2c

[PATCH 1/3] Refactor the handling of the i2cbus command line argument

[Jean Delvare]

Refactor the handling of the I2CBUS parameter. This ensures more
consistency accross the i2c tools.

---
 tools/i2cbusses.c |   24 ++++++++++++++++++++++++
 tools/i2cbusses.h |    1 +
 tools/i2cdetect.c |   11 ++---------
 tools/i2cdump.c   |   10 ++--------
 tools/i2cget.c    |    6 ++----
 tools/i2cset.c    |    6 ++----
 6 files changed, 33 insertions(+), 25 deletions(-)

--- i2c-tools.orig/tools/i2cbusses.c	2008-04-12 11:26:14.000000000 +0200
+++ i2c-tools/tools/i2cbusses.c	2008-04-12 13:31:43.000000000 +0200
@@ -25,6 +25,7 @@
 #include <sys/stat.h>
 #include <string.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <limits.h>
 #include <dirent.h>
@@ -217,6 +218,29 @@ done:
 		               "and also modprobed your i2c bus drivers\n");
 }
 
+/*
+ * 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)
+{
+	long i2cbus;
+	char *end;
+
+	i2cbus = strtol(i2cbus_arg, &end, 0);
+	if (*end || !*i2cbus_arg) {
+		fprintf(stderr, "Error: I2CBUS argument not a number!\n");
+		return -1;
+	}
+	if (i2cbus < 0 || i2cbus > 0xff) {
+		fprintf(stderr, "Error: I2CBUS argument out of range "
+		        "(0-255)!\n");
+		return -2;
+	}
+
+	return i2cbus;
+}
+
 int open_i2c_dev(const int i2cbus, char *filename, const int quiet)
 {
 	int file;
--- i2c-tools.orig/tools/i2cbusses.h	2008-04-12 11:26:14.000000000 +0200
+++ i2c-tools/tools/i2cbusses.h	2008-04-12 11:28:55.000000000 +0200
@@ -24,6 +24,7 @@
 
 void print_i2c_busses(int procfmt);
 
+int lookup_i2c_bus(const char *i2cbus_arg);
 int open_i2c_dev(const int i2cbus, char *filename, const int quiet);
 int set_slave_addr(int file, int address, int force);
 
--- i2c-tools.orig/tools/i2cdetect.c	2008-04-12 11:26:14.000000000 +0200
+++ i2c-tools/tools/i2cdetect.c	2008-04-12 11:28:55.000000000 +0200
@@ -235,15 +235,8 @@ int main(int argc, char *argv[])
 		help();
 		exit(1);
 	}
-	i2cbus = strtol(argv[flags+1], &end, 0);
-	if (*end) {
-		fprintf(stderr, "Error: I2CBUS argument not a number!\n");
-		help();
-		exit(1);
-	}
-	if ((i2cbus < 0) || (i2cbus > 0xff)) {
-		fprintf(stderr, "Error: I2CBUS argument out of range "
-		        "(0-255)!\n");
+	i2cbus = lookup_i2c_bus(argv[flags+1]);
+	if (i2cbus < 0) {
 		help();
 		exit(1);
 	}
--- i2c-tools.orig/tools/i2cdump.c	2008-04-12 11:26:14.000000000 +0200
+++ i2c-tools/tools/i2cdump.c	2008-04-12 11:28:55.000000000 +0200
@@ -91,14 +91,8 @@ int main(int argc, char *argv[])
 		help();
 		exit(1);
 	}
-	i2cbus = strtol(argv[flags+1], &end, 0);
-	if (*end) {
-		fprintf(stderr, "Error: First argument not a number!\n");
-		help();
-		exit(1);
-	}
-	if (i2cbus < 0 || i2cbus > 0xff) {
-		fprintf(stderr, "Error: I2CBUS argument out of range!\n");
+	i2cbus = lookup_i2c_bus(argv[flags+1]);
+	if (i2cbus < 0) {
 		help();
 		exit(1);
 	}
--- i2c-tools.orig/tools/i2cget.c	2008-04-12 11:26:14.000000000 +0200
+++ i2c-tools/tools/i2cget.c	2008-04-12 11:28:55.000000000 +0200
@@ -187,11 +187,9 @@ int main(int argc, char *argv[])
 	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");
+	i2cbus = lookup_i2c_bus(argv[flags+1]);
+	if (i2cbus < 0)
 		help();
-	}
 
 	address = strtol(argv[flags+2], &end, 0);
 	if (*end || address < 3 || address > 0x77) {
--- i2c-tools.orig/tools/i2cset.c	2008-04-12 11:26:14.000000000 +0200
+++ i2c-tools/tools/i2cset.c	2008-04-12 11:28:55.000000000 +0200
@@ -78,11 +78,9 @@ int main(int argc, char *argv[])
 	if (argc < flags + 5)
 		help();
 
-	i2cbus = strtol(argv[flags+1], &end, 0);
-	if (*end || i2cbus < 0 || i2cbus > 0x3f) {
-		fprintf(stderr, "Error: I2CBUS argument invalid!\n");
+	i2cbus = lookup_i2c_bus(argv[flags+1]);
+	if (i2cbus < 0)
 		help();
-	}
 
 	address = strtol(argv[flags+2], &end, 0);
 	if (*end || address < 0 || address > 0x7f) {


-- 
Jean Delvare

_______________________________________________
i2c mailing list
i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org
http://lists.lm-sensors.org/mailman/listinfo/i2c

[PATCH 2/3] Split print_i2c_busses into a gathering part and a printing part

[Jean Delvare]

Split print_i2c_busses into a gathering part and a printing part.

---
 tools/i2cbusses.c |  172 +++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 147 insertions(+), 25 deletions(-)

--- i2c-tools.orig/tools/i2cbusses.c	2008-04-12 13:31:43.000000000 +0200
+++ i2c-tools/tools/i2cbusses.c	2008-04-12 13:41:19.000000000 +0200
@@ -4,6 +4,7 @@
                devices.
     Copyright (c) 1999-2003  Frodo Looijaard <frodol-B0qZmFHriGg@public.gmane.org> and
                              Mark D. Studebaker <mdsxyz123-/E1597aS9LQAvxtiuMwx3w@public.gmane.org>
+    Copyright (C) 2008       Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.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
@@ -54,6 +55,13 @@ static struct adap_type adap_types[5] = 
 	  .algo		= "N/A", },
 };
 
+struct i2c_adap {
+	int nr;
+	char *name;
+	const char *funcs;
+	const char *algo;
+};
+
 static enum adt i2c_get_funcs(int i2cbus)
 {
 	unsigned long funcs;
@@ -80,14 +88,47 @@ static enum adt i2c_get_funcs(int i2cbus
 	return ret;
 }
 
-/*
-   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)
+/* 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;
+}
+
+static 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;
+}
+
+static struct i2c_adap *gather_i2c_busses(void)
 {
 	FILE *fptr;
 	char s[100];
@@ -98,17 +139,51 @@ void print_i2c_busses(int procfmt)
 	char dev[NAME_MAX], 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((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);	
+			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(fptr);
 		goto done;
@@ -189,33 +264,80 @@ found:
 			}
 			if ((border = strchr(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 (!sscanf(de->d_name, "i2c-%d", &i2cbus))
+				continue;
 			if(!strncmp(x, "ISA ", 4)) {
 				type = adt_isa;
-			} else if(!sscanf(de->d_name, "i2c-%d", &i2cbus)) {
-				type = adt_dummy;
 			} else {
 				/* Attempt to probe for adapter capabilities */
 				type = i2c_get_funcs(i2cbus);
 			}
 
-			if (procfmt)
-				printf("%s\t%-10s\t%-32s\t%s\n", de->d_name,
-					adap_types[type].funcs, x, adap_types[type].algo);
-			else
-				fprintf(stderr, "    %s\t%-10s\t%s\n", de->d_name,
-					adap_types[type].funcs, x);
+			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(x);
+			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;
+}
+
+/*
+   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)
+{
+	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++) {
+		if (count == 0 && !procfmt)
+			fprintf(stderr,"  Installed I2C busses:\n");
+		if (procfmt)
+			/* match 2.4 /proc/bus/i2c format as closely as possible */
+			printf("i2c-%d\t%-10s\t%-32s\t%s\n",
+				adapters[count].nr,
+				adapters[count].funcs,
+				adapters[count].name,
+				adapters[count].algo);
+		else
+			fprintf(stderr, "    i2c-%d\t%-10s\t%s\n",
+				adapters[count].nr,
+				adapters[count].funcs,
+				adapters[count].name);
+	}
+
 	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");
+
+	free_adapters(adapters);
 }
 
 /*

-- 
Jean Delvare

_______________________________________________
i2c mailing list
i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org
http://lists.lm-sensors.org/mailman/listinfo/i2c

[PATCH 3/3] Allow passing i2c bus by name

[Jean Delvare]

Make it possible to pass the i2c bus by name instead of by number. As
there is no guarantee that i2c bus numbering will stay the same over
time (for example if hardware is added of removed, or simply due to
loading the drivers in a different order), passing the i2c bus by name
is more robust.

The i2c bus names are supposed to be unique. If you request a bus by
name and this name happens to not be unique, then the tools will play
it safe and quit. This is better than writing to the wrong device.

---
 tools/i2cbusses.c |   38 ++++++++++++++++++++++++++++++++++++--
 tools/i2cdetect.8 |    4 ++--
 tools/i2cdump.8   |    4 ++--
 tools/i2cget.8    |    4 ++--
 tools/i2cset.8    |    4 ++--
 5 files changed, 44 insertions(+), 10 deletions(-)

--- i2c-tools.orig/tools/i2cbusses.c	2008-04-12 13:41:19.000000000 +0200
+++ i2c-tools/tools/i2cbusses.c	2008-04-12 13:41:31.000000000 +0200
@@ -340,6 +340,40 @@ void print_i2c_busses(int procfmt)
 	free_adapters(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: I2CBUS argument doesn't match any "
+			"I2C bus name\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.
@@ -351,8 +385,8 @@ int lookup_i2c_bus(const char *i2cbus_ar
 
 	i2cbus = strtol(i2cbus_arg, &end, 0);
 	if (*end || !*i2cbus_arg) {
-		fprintf(stderr, "Error: I2CBUS argument not a number!\n");
-		return -1;
+		/* Not a number, maybe a name? */
+		return lookup_i2c_bus_by_name(i2cbus_arg);
 	}
 	if (i2cbus < 0 || i2cbus > 0xff) {
 		fprintf(stderr, "Error: I2CBUS argument out of range "
--- i2c-tools.orig/tools/i2cdetect.8	2007-06-27 17:16:10.000000000 +0200
+++ i2c-tools/tools/i2cdetect.8	2008-04-12 13:42:43.000000000 +0200
@@ -1,4 +1,4 @@
-.TH I2CDETECT 8 "June 2007"
+.TH I2CDETECT 8 "April 2008"
 .SH NAME
 i2cdetect \- detect I2C chips
 
@@ -23,7 +23,7 @@ i2cdetect \- detect I2C chips
 .SH DESCRIPTION
 i2cdetect is a userspace program to scan an I2C bus for devices. It
 outputs a table with the list of detected devices on the specified bus.
-\fIi2cbus\fR indicates the number of the I2C bus to be scanned, and
+\fIi2cbus\fR indicates the number or name of the I2C bus to be scanned, and
 should correspond to one of the busses listed by \fIi2cdetect -l\fR.
 The optional parameters \fIfirst\fR and \fIlast\fR restrict the scanning
 range (default: from 0x03 to 0x77).
--- i2c-tools.orig/tools/i2cdump.8	2008-03-11 13:49:27.000000000 +0100
+++ i2c-tools/tools/i2cdump.8	2008-04-12 13:42:51.000000000 +0200
@@ -1,4 +1,4 @@
-.TH I2CDUMP 8 "March 2008"
+.TH I2CDUMP 8 "April 2008"
 .SH NAME
 i2cdump \- examine I2C registers
 
@@ -43,7 +43,7 @@ will perform the operation directly. Thi
 scripts.
 .PP
 At least two options must be provided to i2cdump. \fIi2cbus\fR indicates the
-number of the I2C bus to be scanned. This number should correspond to one
+number or name of the I2C bus to be scanned. This number should correspond to one
 of the busses listed by \fIi2cdetect -l\fR. \fIaddress\fR indicates the
 address to be scanned on that bus, and is an integer between 0x00 and 0x7F.
 .PP
--- i2c-tools.orig/tools/i2cget.8	2007-06-27 17:16:10.000000000 +0200
+++ i2c-tools/tools/i2cget.8	2008-04-12 13:43:00.000000000 +0200
@@ -1,4 +1,4 @@
-.TH I2CGET 8 "June 2007"
+.TH I2CGET 8 "April 2008"
 .SH "NAME"
 i2cget \- read from I2C/SMBus chip registers
 
@@ -36,7 +36,7 @@ will perform the operation directly. Thi
 scripts. Use with caution.
 .PP
 There are two required options to i2cget. \fIi2cbus\fR indicates the number
-of the I2C bus to be scanned.  This number should correspond to one of
+or name of the I2C bus to be scanned.  This number should correspond to one of
 the busses listed by \fIi2cdetect -l\fR. \fIchip-address\fR specifies the
 address of the chip on that bus, and is an integer between 0x03 and 0x77.
 .PP
--- i2c-tools.orig/tools/i2cset.8	2007-06-27 17:16:10.000000000 +0200
+++ i2c-tools/tools/i2cset.8	2008-04-12 13:43:07.000000000 +0200
@@ -1,4 +1,4 @@
-.TH I2CSET 8 "June 2007"
+.TH I2CSET 8 "April 2008"
 .SH "NAME"
 i2cset \- set I2C registers
 
@@ -40,7 +40,7 @@ will perform the operation directly. Thi
 scripts.
 .PP
 There are four required options to i2cset. \fIi2cbus\fR indicates the number
-of the I2C bus to be scanned.  This number should correspond to one of
+or name of the I2C bus to be scanned.  This number should correspond to one of
 the busses listed by \fIi2cdetect -l\fR. \fIchip-address\fR specifies the
 address of the chip on that bus, and is an integer between 0x00 and 0x7F.
 \fIdata-address\fR specifies the address on that chip to write to, and is an


-- 
Jean Delvare

_______________________________________________
i2c mailing list
i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org
http://lists.lm-sensors.org/mailman/listinfo/i2c