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Thanks Dan!
Updated and a bit refactored patch is attached.
Michal
On 07/17/2014 02:56 AM, Danielle Costantino wrote:
> you need to add this after the #else , before the err = system...
> to accommodate for systems that have i2c-dev.ko built in, not as a
> module, on older kernels.
>
> struct stat st;
>
> err = stat("/sys/class/i2c-dev", &st);
>
> if (err < 0) { if (errno != ENOENT) { err = -errno; goto done; }
> else err = 0; } else return 1;
>
>
>
> On Wed, Jul 16, 2014 at 10:14 AM, Wolfram Sang <wsa@xxxxxxxxxxxxx>
> wrote:
>
>>
>> Adding Jean Delvare who maintains i2c-tools to CC...
>>
>> On Thu, Jun 05, 2014 at 10:17:33AM +0200, Michal Minář wrote:
> Hello,
>
> we've got following request (viz [1]):
>
> i2cdetect requires the i2c-dev module be loaded so the appropriate
> /dev entries are created. This is not done automatically, so when
> i2cdetect is initially run it gives the false impression that no
> buses/devices exist:
>
> # i2cdetect -l # modprobe i2c-dev # i2cdetect -l i2c-0 i2c
> i915 gmbus ssc I2C adapter i2c-1 i2c
> i915 gmbus vga I2C adapter i2c-2 i2c
> i915 gmbus panel I2C adapter i2c-3 i2c
> i915 gmbus dpc I2C adapter i2c-4 i2c
> i915 gmbus dpb I2C adapter i2c-5 i2c
> i915 gmbus dpd I2C adapter i2c-6 i2c
> DPDDC-C I2C adapter i2c-7 i2c
> DPDDC-D I2C adapter
>
>
> Attached is a patch that autoloads i2c-dev module when neccessary.
> If you like it and have commit rights, push it please instead of
> me. If you don't like it, don't hold back and tell me.
>
> Best regards, Michal Minar
>
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=913203
>>
>>> Index: i2c-tools-3.1.0/tools/i2cbusses.c
>>> ===================================================================
>>>
>>>
- --- i2c-tools-3.1.0.orig/tools/i2cbusses.c
>>> +++ i2c-tools-3.1.0/tools/i2cbusses.c @@ -37,9 +37,15 @@
>>> #include <dirent.h> #include <fcntl.h> #include <errno.h>
>>> +#ifdef USE_LIBKMOD + #include <libkmod.h> +#endif #include
>>> "i2cbusses.h" #include <linux/i2c-dev.h>
>>>
>>> +#define BUFLEN 512 +#define I2C_DEV_MOD_NAME "i2c_dev" + enum
>>> adt { adt_dummy, adt_isa, adt_i2c, adt_smbus, adt_unknown };
>>>
>>> struct adap_type { @@ -60,6 +66,70 @@ static struct adap_type
>>> adap_types[5] = .algo = "N/A", }, };
>>>
>>> +/** + * Try to load i2c_dev kernel mode. Do nothing, if module
>>> is already
>> loaded.
>>> + * Returns 1 on success, 0 otherwise. + */ +static int
>>> try_load_i2c_dev_mod(void) { + int err = 0, loaded = 0; +
>>> char errbuf[BUFLEN] = { 0 }; +#ifdef USE_LIBKMOD + int
>>> flags = 0; + struct kmod_ctx *ctx; + struct kmod_list
>>> *l, *list = NULL; + + ctx = kmod_new(NULL, NULL); + if
>>> (!ctx) { + snprintf(errbuf, BUFLEN, "kmod_new()
>>> failed!"); + goto done; + } + if
>>> (kmod_module_new_from_lookup(ctx, I2C_DEV_MOD_NAME, &list) < 0
>> || list == NULL) {
>>> + snprintf(errbuf, BUFLEN, I2C_DEV_MOD_NAME "
>>> module lookup
>> failed");
>>> + goto ctx_unref; + } + + flags |=
>>> KMOD_PROBE_APPLY_BLACKLIST_ALIAS_ONLY; +
>>> kmod_list_foreach(l, list) { + struct kmod_module
>>> *mod = kmod_module_get_module(l); + err =
>>> kmod_module_probe_insert_module(mod, flags, NULL,
>> NULL, NULL, NULL);
>>> + if (err == -ENOENT) { +
>>> snprintf(errbuf, BUFLEN, +
>>> "unknown symbol in module \"%s\",
>> or unknown parameter (see dmesg)",
>>> +
>>> kmod_module_get_name(mod)); + } else if (err < 0)
>>> { + snprintf(errbuf, BUFLEN, "(module %s):
>>> %s", +
>>> kmod_module_get_name(mod),
>> strerror(-err));
>>> + } else { +
>>> kmod_module_unref(mod); + ++loaded; +
>>> break; + } + kmod_module_unref(mod); +
>>> } + +list_unref: + kmod_module_unref_list(list);
>>> +ctx_unref: + kmod_unref(ctx); +#else + err =
>>> system("modprobe " I2C_DEV_MOD_NAME); + if (err < 0) { +
>>> snprintf(errbuf, BUFLEN, "failed to execute modprobe
>> command");
>>> + } else if (err > 0) { + snprintf(errbuf,
>>> BUFLEN, "modprobe command exited with
>> code %d",
>>> + WEXITSTATUS(err)); + } else
>>> { + ++loaded; + goto done; + }
>>> +#endif + if (errbuf[0]) + fprintf(stderr,
>>> "Failed to load required " I2C_DEV_MOD_NAME +
>>> " kernel module: %s\n", errbuf); +done: + return loaded;
>>> +} + static enum adt i2c_get_funcs(int i2cbus) { unsigned long
>>> funcs; @@ -206,8 +276,12 @@ struct i2c_adap
>>> *gather_i2c_busses(void) 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; +
>>> if(!(dir = opendir(sysfs))) { + if
>>> (!try_load_i2c_dev_mod()) + goto done; +
>>> if ((!(dir = opendir(sysfs)))) + goto
>>> done; + } /* go through the busses */ while ((de =
>>> readdir(dir)) != NULL) { if (!strcmp(de->d_name, ".")) Index:
>>> i2c-tools-3.1.0/tools/Module.mk
>>> ===================================================================
>>>
>>>
- --- i2c-tools-3.1.0.orig/tools/Module.mk
>>> +++ i2c-tools-3.1.0/tools/Module.mk @@ -15,6 +15,11 @@
>>> TOOLS_CFLAGS := -Wstrict-prototypes -Wsh
>>>
>>> TOOLS_TARGETS := i2cdetect i2cdump i2cset i2cget
>>>
>>> +ifeq ($(shell pkg-config --exists libkmod && echo 1), 1) +
>>> TOOLS_CFLAGS += $(shell pkg-config --cflags libkmod)
>>> -DUSE_LIBKMOD + LDFLAGS += $(shell pkg-config --libs
>>> libkmod) +endif + # # Programs #
>>
>>
>>
>
>
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Index: i2c-tools/tools/i2cbusses.c
===================================================================
--- i2c-tools.orig/tools/i2cbusses.c
+++ i2c-tools/tools/i2cbusses.c
@@ -38,10 +38,17 @@
#include <dirent.h>
#include <fcntl.h>
#include <errno.h>
+#ifdef USE_LIBKMOD
+ #include <libkmod.h>
+#endif
#include "i2cbusses.h"
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
+#define BUFLEN (NAME_MAX > 512 ? NAME_MAX : 512)
+#define I2C_DEV_MOD_NAME "i2c_dev"
+#define I2C_DEV_SUBPATH "/class/i2c-dev"
+
enum adt { adt_dummy, adt_isa, adt_i2c, adt_smbus, adt_unknown };
struct adap_type {
@@ -62,6 +69,142 @@ static struct adap_type adap_types[5] =
.algo = "N/A", },
};
+/* Get and cache sysfs mount point. */
+static const char *get_sysfs_mount_point(void) {
+ static const char *mp = NULL;
+
+ if (mp == NULL) {
+ char sysfs[NAME_MAX];
+ char fstype[NAME_MAX];
+ char line[BUFLEN];
+ FILE *f;
+
+ if ((f = fopen("/proc/mounts", "r")) == NULL) {
+ perror("failed to read /proc/mounts: ");
+ goto done;
+ }
+ while (fgets(line, BUFLEN, f)) {
+ sscanf(line, "%*[^ ] %[^ ] %[^ ] %*s\n", sysfs, fstype);
+ if (strcasecmp(fstype, "sysfs") == 0) {
+ mp = strdup(sysfs);
+ if (mp == NULL)
+ perror("strdup: ");
+ break;
+ }
+ }
+ fclose(f);
+ }
+done:
+ return mp;
+}
+
+/* Get an absolute path of i2c device directory. Free the result when not
+ * needed. */
+static char *get_i2c_dev_path(void) {
+ char *path = NULL;
+ int mplen, splen;
+ const char *mp = get_sysfs_mount_point();
+
+ if (mp != NULL) {
+ mplen = strlen(mp);
+ splen = strlen(I2C_DEV_SUBPATH);
+ path = malloc(mplen + splen + 1);
+ if (path == NULL) {
+ perror("malloc: ");
+ } else {
+ strncpy(path, mp, mplen);
+ strncpy(path + mplen, I2C_DEV_SUBPATH, splen);
+ path[mplen+splen] = '\0';
+ }
+ }
+ return path;
+}
+
+/**
+ * Try to load i2c_dev kernel mode. Do nothing if module is already loaded.
+ * Returns 1 on success, 0 otherwise.
+ */
+static int try_load_i2c_dev_mod(void) {
+ int err = 0, loaded = 0;
+ char errbuf[BUFLEN] = { 0 };
+#ifdef USE_LIBKMOD
+ int flags = 0;
+ struct kmod_ctx *ctx;
+ struct kmod_list *l, *list = NULL;
+
+ ctx = kmod_new(NULL, NULL);
+ if (!ctx) {
+ snprintf(errbuf, BUFLEN, "kmod_new() failed!");
+ goto done;
+ }
+ if (kmod_module_new_from_lookup(ctx, I2C_DEV_MOD_NAME, &list) < 0 || list == NULL) {
+ snprintf(errbuf, BUFLEN, I2C_DEV_MOD_NAME " module lookup failed");
+ goto ctx_unref;
+ }
+
+ flags |= KMOD_PROBE_APPLY_BLACKLIST_ALIAS_ONLY;
+ kmod_list_foreach(l, list) {
+ struct kmod_module *mod = kmod_module_get_module(l);
+ err = kmod_module_probe_insert_module(mod, flags, NULL, NULL, NULL, NULL);
+ if (err == -ENOENT) {
+ snprintf(errbuf, BUFLEN,
+ "unknown symbol in module \"%s\", or unknown parameter (see dmesg)",
+ kmod_module_get_name(mod));
+ } else if (err < 0) {
+ snprintf(errbuf, BUFLEN, "(module %s): %s",
+ kmod_module_get_name(mod), strerror(-err));
+ } else {
+ kmod_module_unref(mod);
+ ++loaded;
+ break;
+ }
+ kmod_module_unref(mod);
+ }
+
+ kmod_module_unref_list(list);
+ctx_unref:
+ kmod_unref(ctx);
+#else /* Try to load the module with modprobe. */
+ struct stat st;
+ char *dev_path = get_i2c_dev_path();
+
+ /* First check whether the module is already loaded or built-in. */
+ if (dev_path == NULL)
+ goto done;
+ err = stat(dev_path, &st);
+ if (err < 0) {
+ if (errno != ENOENT) {
+ snprintf(errbuf, BUFLEN, "can not stat \"%s\": %s", dev_path,
+ strerror(errno));
+ goto err;
+ } else {
+ err = 0;
+ }
+ } else {
+ ++loaded;
+ goto done;
+ }
+
+ err = system("modprobe " I2C_DEV_MOD_NAME);
+ if (err < 0) {
+ snprintf(errbuf, BUFLEN, "failed to execute modprobe command");
+ } else if (err > 0) {
+ snprintf(errbuf, BUFLEN, "modprobe command exited with code %d",
+ WEXITSTATUS(err));
+ } else {
+ ++loaded;
+ goto done;
+ }
+
+err:
+#endif
+ if (errbuf[0])
+ fprintf(stderr, "Failed to load required " I2C_DEV_MOD_NAME
+ " kernel module: %s\n", errbuf);
+done:
+ return loaded;
+}
+
static enum adt i2c_get_funcs(int i2cbus)
{
unsigned long funcs;
@@ -134,8 +277,7 @@ struct i2c_adap *gather_i2c_busses(void)
struct dirent *de, *dde;
DIR *dir, *ddir;
FILE *f;
- char fstype[NAME_MAX], sysfs[NAME_MAX], n[NAME_MAX];
- int foundsysfs = 0;
+ char *sysfs = NULL, n[NAME_MAX];
int count=0;
struct i2c_adap *adapters;
@@ -187,29 +329,19 @@ struct i2c_adap *gather_i2c_busses(void)
goto done;
}
- /* look in sysfs */
- /* First figure out where sysfs was mounted */
- if ((f = fopen("/proc/mounts", "r")) == NULL) {
+ sysfs = get_i2c_dev_path();
+ if (sysfs == 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;
+ if(!(dir = opendir(sysfs))) {
+ if (!try_load_i2c_dev_mod())
+ goto done;
+ if ((!(dir = opendir(sysfs))))
+ goto done;
+ }
/* go through the busses */
while ((de = readdir(dir)) != NULL) {
if (!strcmp(de->d_name, "."))
@@ -274,14 +406,15 @@ found:
/* We need more space */
adapters = more_adapters(adapters, count + 1);
if (!adapters)
- return NULL;
+ goto done;
}
adapters[count].nr = i2cbus;
adapters[count].name = strdup(s);
if (adapters[count].name == NULL) {
free_adapters(adapters);
- return NULL;
+ adapters = NULL;
+ goto done;
}
adapters[count].funcs = adap_types[type].funcs;
adapters[count].algo = adap_types[type].algo;
@@ -291,6 +424,7 @@ found:
closedir(dir);
done:
+ free(sysfs);
return adapters;
}
Index: i2c-tools/tools/Module.mk
===================================================================
--- i2c-tools.orig/tools/Module.mk
+++ i2c-tools/tools/Module.mk
@@ -16,6 +16,11 @@ TOOLS_LDFLAGS := -Llib -li2c
TOOLS_TARGETS := i2cdetect i2cdump i2cset i2cget
+ifeq ($(shell pkg-config --exists libkmod && echo 1), 1)
+ TOOLS_CFLAGS += $(shell pkg-config --cflags libkmod) -DUSE_LIBKMOD
+ LDFLAGS += $(shell pkg-config --libs libkmod)
+endif
+
#
# Programs
#
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