Deal with iio trigger names

This will clean (disable buffer/trigger/channels) when doing something like a CTRL-C. Otherwise restarting generic_buffer requires a manual echo 0 > buffer/enable

This also cleanup up all the code freeing string buffers at the end of main. We initialize all pointers to NULL so that cleanup can all be done under a single error label.

Signed-off-by Crestez Dan Leonard <[email protected]>

---
Changes since v2: Initialize data to NULL to prevent crash on free.

 tools/iio/generic_buffer.c | 172 ++++++++++++++++++++++++++++-----------------
 1 file changed, 108 insertions(+), 64 deletions(-)

tools/iio/generic_buffer.c +108 -64

index 2429c78..972f400 100644
@@ -32,6 +32,8 @@
 #include <endian.h>
 #include <getopt.h>
 #include <inttypes.h>
+#include <stdbool.h>
+#include <signal.h>
 #include "iio_utils.h"
 
 /**

@@ -254,6 +256,65 @@ void print_usage(void)
 		"  -w <n>     Set delay between reads in us (event-less mode)\n");
 }
 
+enum autochan autochannels = AUTOCHANNELS_DISABLED;
+char *dev_dir_name = NULL;
+char *buf_dir_name = NULL;
+bool current_trigger_set = false;
+
+void cleanup(void)
+{
+	int ret;
+
+	/* Disable trigger */
+	if (dev_dir_name && current_trigger_set) {
+		/* Disconnect the trigger - just write a dummy name. */
+		ret = write_sysfs_string("trigger/current_trigger",
+					 dev_dir_name, "NULL");
+		if (ret < 0)
+			fprintf(stderr, "Failed to disable trigger: %s\n",
+				strerror(-ret));
+		current_trigger_set = false;
+	}
+
+	/* Disable buffer */
+	if (buf_dir_name) {
+		ret = write_sysfs_int("enable", buf_dir_name, 0);
+		if (ret < 0)
+			fprintf(stderr, "Failed to disable buffer: %s\n",
+				strerror(-ret));
+	}
+
+	/* Disable channels if auto-enabled */
+	if (dev_dir_name && autochannels == AUTOCHANNELS_ACTIVE) {
+		ret = enable_disable_all_channels(dev_dir_name, 0);
+		if (ret)
+			fprintf(stderr, "Failed to disable all channels\n");
+		autochannels = AUTOCHANNELS_DISABLED;
+	}
+}
+
+void sig_handler(int signum)
+{
+	fprintf(stderr, "Caught signal %d\n", signum);
+	cleanup();
+	exit(-signum);
+}
+
+void register_cleanup(void)
+{
+	struct sigaction sa = { .sa_handler = sig_handler };
+	const int signums[] = { SIGINT, SIGTERM, SIGABRT };
+	int ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(signums); ++i) {
+		ret = sigaction(signums[i], &sa, NULL);
+		if (ret) {
+			perror("Failed to register signal handler");
+			exit(-1);
+		}
+	}
+}
+
 int main(int argc, char **argv)
 {
 	unsigned long num_loops = 2;

@@ -261,25 +322,24 @@ int main(int argc, char **argv)
 	unsigned long buf_len = 128;
 
 	int ret, c, i, j, toread;
-	int fp;
+	int fp = -1;
 
-	int num_channels;
+	int num_channels = 0;
 	char *trigger_name = NULL, *device_name = NULL;
-	char *dev_dir_name, *buf_dir_name;
 
-	int datardytrigger = 1;
-	char *data;
+	char *data = NULL;
 	ssize_t read_size;
 	int dev_num, trig_num;
-	char *buffer_access;
+	char *buffer_access = NULL;
 	int scan_size;
 	int noevents = 0;
 	int notrigger = 0;
-	enum autochan autochannels = AUTOCHANNELS_DISABLED;
 	char *dummy;
 
 	struct iio_channel_info *channels;
 
+	register_cleanup();
+
 	while ((c = getopt(argc, argv, "ac:egl:n:t:w:")) != -1) {
 		switch (c) {
 		case 'a':

@@ -288,8 +348,10 @@ int main(int argc, char **argv)
 		case 'c':
 			errno = 0;
 			num_loops = strtoul(optarg, &dummy, 10);
-			if (errno)
-				return -errno;
+			if (errno) {
+				ret = -errno;
+				goto error;
+			}
 
 			break;
 		case 'e':

@@ -301,26 +363,30 @@ int main(int argc, char **argv)
 		case 'l':
 			errno = 0;
 			buf_len = strtoul(optarg, &dummy, 10);
-			if (errno)
-				return -errno;
+			if (errno) {
+				ret = -errno;
+				goto error;
+			}
 
 			break;
 		case 'n':
 			device_name = optarg;
 			break;
 		case 't':
-			trigger_name = optarg;
-			datardytrigger = 0;
+			trigger_name = strdup(optarg);
 			break;
 		case 'w':
 			errno = 0;
 			timedelay = strtoul(optarg, &dummy, 10);
-			if (errno)
-				return -errno;
+			if (errno) {
+				ret = -errno;
+				goto error;
+			}
 			break;
 		case '?':
 			print_usage();
-			return -1;
+			ret = -1;
+			goto error;
 		}
 	}
 

@@ -334,14 +400,17 @@ int main(int argc, char **argv)
 	dev_num = find_type_by_name(device_name, "iio:device");
 	if (dev_num < 0) {
 		fprintf(stderr, "Failed to find the %s\n", device_name);
-		return dev_num;
+		ret = dev_num;
+		goto error;
 	}
 
 	printf("iio device number being used is %d\n", dev_num);
 
 	ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
-	if (ret < 0)
-		return -ENOMEM;
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto error;
+	}
 
 	if (!notrigger) {
 		if (!trigger_name) {

@@ -354,7 +423,7 @@ int main(int argc, char **argv)
 				       "%s-dev%d", device_name, dev_num);
 			if (ret < 0) {
 				ret = -ENOMEM;
-				goto error_free_dev_dir_name;
+				goto error;
 			}
 		}
 

@@ -367,7 +436,7 @@ int main(int argc, char **argv)
 				       "%s-trigger", device_name);
 			if (ret < 0) {
 				ret = -ENOMEM;
-				goto error_free_dev_dir_name;
+				goto error;
 			}
 		}
 

@@ -376,7 +445,7 @@ int main(int argc, char **argv)
 			fprintf(stderr, "Failed to find the trigger %s\n",
 				trigger_name);
 			ret = trig_num;
-			goto error_free_triggername;
+			goto error;
 		}
 
 		printf("iio trigger number being used is %d\n", trig_num);

@@ -392,7 +461,7 @@ int main(int argc, char **argv)
 	if (ret) {
 		fprintf(stderr, "Problem reading scan element information\n"
 			"diag %s\n", dev_dir_name);
-		goto error_free_triggername;
+		goto error;
 	}
 	if (num_channels && autochannels == AUTOCHANNELS_ENABLED) {
 		fprintf(stderr, "Auto-channels selected but some channels "

@@ -407,7 +476,7 @@ int main(int argc, char **argv)
 		ret = enable_disable_all_channels(dev_dir_name, 1);
 		if (ret) {
 			fprintf(stderr, "Failed to enable all channels\n");
-			goto error_free_triggername;
+			goto error;
 		}
 
 		/* This flags that we need to disable the channels again */

@@ -419,12 +488,12 @@ int main(int argc, char **argv)
 			fprintf(stderr, "Problem reading scan element "
 				"information\n"
 				"diag %s\n", dev_dir_name);
-			goto error_disable_channels;
+			goto error;
 		}
 		if (!num_channels) {
 			fprintf(stderr, "Still no channels after "
 				"auto-enabling, giving up\n");
-			goto error_disable_channels;
+			goto error;
 		}
 	}
 

@@ -436,7 +505,7 @@ int main(int argc, char **argv)
 			"/*_en or pass -a to autoenable channels and "
 			"try again.\n", dev_dir_name);
 		ret = -ENOENT;
-		goto error_free_triggername;
+		goto error;
 	}
 
 	/*

@@ -448,7 +517,7 @@ int main(int argc, char **argv)
 		       "%siio:device%d/buffer", iio_dir, dev_num);
 	if (ret < 0) {
 		ret = -ENOMEM;
-		goto error_free_channels;
+		goto error;
 	}
 
 	if (!notrigger) {

@@ -463,34 +532,34 @@ int main(int argc, char **argv)
 		if (ret < 0) {
 			fprintf(stderr,
 				"Failed to write current_trigger file\n");
-			goto error_free_buf_dir_name;
+			goto error;
 		}
 	}
 
 	/* Setup ring buffer parameters */
 	ret = write_sysfs_int("length", buf_dir_name, buf_len);
 	if (ret < 0)
-		goto error_free_buf_dir_name;
+		goto error;
 
 	/* Enable the buffer */
 	ret = write_sysfs_int("enable", buf_dir_name, 1);
 	if (ret < 0) {
 		fprintf(stderr,
 			"Failed to enable buffer: %s\n", strerror(-ret));
-		goto error_free_buf_dir_name;
+		goto error;
 	}
 
 	scan_size = size_from_channelarray(channels, num_channels);
 	data = malloc(scan_size * buf_len);
 	if (!data) {
 		ret = -ENOMEM;
-		goto error_free_buf_dir_name;
+		goto error;
 	}
 
 	ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
 	if (ret < 0) {
 		ret = -ENOMEM;
-		goto error_free_data;
+		goto error;
 	}
 
 	/* Attempt to open non blocking the access dev */

@@ -498,7 +567,7 @@ int main(int argc, char **argv)
 	if (fp == -1) { /* TODO: If it isn't there make the node */
 		ret = -errno;
 		fprintf(stderr, "Failed to open %s\n", buffer_access);
-		goto error_free_buffer_access;
+		goto error;
 	}
 
 	for (j = 0; j < num_loops; j++) {

@@ -511,7 +580,7 @@ int main(int argc, char **argv)
 			ret = poll(&pfd, 1, -1);
 			if (ret < 0) {
 				ret = -errno;
-				goto error_close_buffer_access;
+				goto error;
 			} else if (ret == 0) {
 				continue;
 			}

@@ -536,45 +605,20 @@ int main(int argc, char **argv)
 				     num_channels);
 	}
 
-	/* Stop the buffer */
-	ret = write_sysfs_int("enable", buf_dir_name, 0);
-	if (ret < 0)
-		goto error_close_buffer_access;
-
-	if (!notrigger)
-		/* Disconnect the trigger - just write a dummy name. */
-		ret = write_sysfs_string("trigger/current_trigger",
-					 dev_dir_name, "NULL");
-		if (ret < 0)
-			fprintf(stderr, "Failed to write to %s\n",
-				dev_dir_name);
+error:
+	cleanup();
 
-error_close_buffer_access:
-	if (close(fp) == -1)
+	if (fp >= 0 && close(fp) == -1)
 		perror("Failed to close buffer");
-
-error_free_buffer_access:
 	free(buffer_access);
-error_free_data:
 	free(data);
-error_free_buf_dir_name:
 	free(buf_dir_name);
-error_free_channels:
 	for (i = num_channels - 1; i >= 0; i--) {
 		free(channels[i].name);
 		free(channels[i].generic_name);
 	}
 	free(channels);
-error_free_triggername:
-	if (datardytrigger)
-		free(trigger_name);
-error_disable_channels:
-	if (autochannels == AUTOCHANNELS_ACTIVE) {
-		ret = enable_disable_all_channels(dev_dir_name, 0);
-		if (ret)
-			fprintf(stderr, "Failed to disable all channels\n");
-	}
-error_free_dev_dir_name:
+	free(trigger_name);
 	free(dev_dir_name);
 
 	return ret;

This makes it possible to distinguish between iio devices with the same name.

Signed-off-by Crestez Dan Leonard <[email protected]>

---
 tools/iio/generic_buffer.c | 69 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 51 insertions(+), 18 deletions(-)

tools/iio/generic_buffer.c +51 -18

index 972f400..3f16e9f 100644
@@ -251,7 +251,9 @@ void print_usage(void)
 		"  -e         Disable wait for event (new data)\n"
 		"  -g         Use trigger-less mode\n"
 		"  -l <n>     Set buffer length to n samples\n"
-		"  -n <name>  Set device name (mandatory)\n"
+		"  --device-name -n <name>\n"
+		"  --device-num -N <num>\n"
+		"        Set device by name or number (mandatory)\n"
 		"  -t <name>  Set trigger name\n"
 		"  -w <n>     Set delay between reads in us (event-less mode)\n");
 }

@@ -315,6 +317,12 @@ void register_cleanup(void)
 	}
 }
 
+static const struct option longopts[] = {
+	{ "device-name",	1, 0, 'n' },
+	{ "device-num",		1, 0, 'N' },
+	{ },
+};
+
 int main(int argc, char **argv)
 {
 	unsigned long num_loops = 2;

@@ -329,7 +337,7 @@ int main(int argc, char **argv)
 
 	char *data = NULL;
 	ssize_t read_size;
-	int dev_num, trig_num;
+	int dev_num = -1, trig_num;
 	char *buffer_access = NULL;
 	int scan_size;
 	int noevents = 0;

@@ -340,7 +348,7 @@ int main(int argc, char **argv)
 
 	register_cleanup();
 
-	while ((c = getopt(argc, argv, "ac:egl:n:t:w:")) != -1) {
+	while ((c = getopt_long(argc, argv, "ac:egl:n:N:t:w:", longopts, NULL)) != -1) {
 		switch (c) {
 		case 'a':
 			autochannels = AUTOCHANNELS_ENABLED;

@@ -370,7 +378,15 @@ int main(int argc, char **argv)
 
 			break;
 		case 'n':
-			device_name = optarg;
+			device_name = strdup(optarg);
+			break;
+		case 'N':
+			errno = 0;
+			dev_num = strtoul(optarg, &dummy, 10);
+			if (errno) {
+				ret = -errno;
+				goto error;
+			}
 			break;
 		case 't':
 			trigger_name = strdup(optarg);

@@ -390,26 +406,42 @@ int main(int argc, char **argv)
 		}
 	}
 
-	if (!device_name) {
-		fprintf(stderr, "Device name not set\n");
-		print_usage();
-		return -1;
-	}
-
 	/* Find the device requested */
-	dev_num = find_type_by_name(device_name, "iio:device");
-	if (dev_num < 0) {
-		fprintf(stderr, "Failed to find the %s\n", device_name);
-		ret = dev_num;
+	if (dev_num < 0 && !device_name) {
+		fprintf(stderr, "Device not set\n");
+		print_usage();
+		ret = -1;
+		goto error;
+	} else if (dev_num >= 0 && device_name) {
+		fprintf(stderr, "Only one of --device-num or --device-name needs to be set\n");
+		print_usage();
+		ret = -1;
 		goto error;
+	} else if (dev_num < 0) {
+		dev_num = find_type_by_name(device_name, "iio:device");
+		if (dev_num < 0) {
+			fprintf(stderr, "Failed to find the %s\n", device_name);
+			ret = dev_num;
+			goto error;
+		}
 	}
-
 	printf("iio device number being used is %d\n", dev_num);
 
 	ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
-	if (ret < 0) {
-		ret = -ENOMEM;
-		goto error;
+	if (ret < 0)
+		return -ENOMEM;
+	/* Fetch device_name if specified by number */
+	if (!device_name) {
+		device_name = malloc(IIO_MAX_NAME_LENGTH);
+		if (!device_name) {
+			ret = -ENOMEM;
+			goto error;
+		}
+		ret = read_sysfs_string("name", dev_dir_name, device_name);
+		if (ret < 0) {
+			fprintf(stderr, "Failed to read name of device %d\n", dev_num);
+			goto error;
+		}
 	}
 
 	if (!notrigger) {

@@ -619,6 +651,7 @@ error:
 	}
 	free(channels);
 	free(trigger_name);
+	free(device_name);
 	free(dev_dir_name);
 
 	return ret;

Signed-off-by Crestez Dan Leonard <[email protected]>

---
 tools/iio/generic_buffer.c | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

tools/iio/generic_buffer.c +29 -5

index 3f16e9f..e8c3052 100644
@@ -254,7 +254,9 @@ void print_usage(void)
 		"  --device-name -n <name>\n"
 		"  --device-num -N <num>\n"
 		"        Set device by name or number (mandatory)\n"
-		"  -t <name>  Set trigger name\n"
+		"  --trigger-name -t <name>\n"
+		"  --trigger-num -T <num>\n"
+		"        Set trigger by name or number\n"
 		"  -w <n>     Set delay between reads in us (event-less mode)\n");
 }
 

@@ -320,6 +322,8 @@ void register_cleanup(void)
 static const struct option longopts[] = {
 	{ "device-name",	1, 0, 'n' },
 	{ "device-num",		1, 0, 'N' },
+	{ "trigger-name",	1, 0, 't' },
+	{ "trigger-num",	1, 0, 'T' },
 	{ },
 };
 

@@ -348,7 +352,7 @@ int main(int argc, char **argv)
 
 	register_cleanup();
 
-	while ((c = getopt_long(argc, argv, "ac:egl:n:N:t:w:", longopts, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "ac:egl:n:N:t:T:w:", longopts, NULL)) != -1) {
 		switch (c) {
 		case 'a':
 			autochannels = AUTOCHANNELS_ENABLED;

@@ -391,6 +395,12 @@ int main(int argc, char **argv)
 		case 't':
 			trigger_name = strdup(optarg);
 			break;
+		case 'T':
+			errno = 0;
+			trig_num = strtoul(optarg, &dummy, 10);
+			if (errno)
+				return -errno;
+			break;
 		case 'w':
 			errno = 0;
 			timedelay = strtoul(optarg, &dummy, 10);

@@ -444,7 +454,23 @@ int main(int argc, char **argv)
 		}
 	}
 
-	if (!notrigger) {
+	if (notrigger) {
+		printf("trigger-less mode selected\n");
+	} if (trig_num > 0) {
+		char *trig_dev_name;
+		ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num);
+		if (ret < 0) {
+			return -ENOMEM;
+		}
+		trigger_name = malloc(IIO_MAX_NAME_LENGTH);
+		ret = read_sysfs_string("name", trig_dev_name, trigger_name);
+		free(trig_dev_name);
+		if (ret < 0) {
+			fprintf(stderr, "Failed to read trigger%d name from\n", trig_num);
+			return ret;
+		}
+		printf("iio trigger number being used is %d\n", trig_num);
+	} else {
 		if (!trigger_name) {
 			/*
 			 * Build the trigger name. If it is device associated

@@ -481,8 +507,6 @@ int main(int argc, char **argv)
 		}
 
 		printf("iio trigger number being used is %d\n", trig_num);
-	} else {
-		printf("trigger-less mode selected\n");
 	}
 
 	/*

This allows controlling the current trigger by numeric ID rather than name.

The trigger name is documented as unique but drivers are currently allowed to register triggers with duplicate names. This should be considered a bug since it makes the 'current_trigger' interface unusable.

Signed-off-by Crestez Dan Leonard <[email protected]>

---
 drivers/iio/industrialio-trigger.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

drivers/iio/industrialio-trigger.c +21 -0

index e79c64c..e77503c 100644
@@ -64,6 +64,8 @@ static struct attribute *iio_trig_dev_attrs[] = {
 };
 ATTRIBUTE_GROUPS(iio_trig_dev);
 
+static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
+
 int iio_trigger_register(struct iio_trigger *trig_info)
 {
 	int ret;

@@ -82,11 +84,18 @@ int iio_trigger_register(struct iio_trigger *trig_info)
 
 	/* Add to list of available triggers held by the IIO core */
 	mutex_lock(&iio_trigger_list_lock);
+	if (__iio_trigger_find_by_name(trig_info->name)) {
+		pr_err("Duplicate trigger name '%s'\n", trig_info->name);
+		ret = -EEXIST;
+		goto error_device_del;
+	}
 	list_add_tail(&trig_info->list, &iio_trigger_list);
 	mutex_unlock(&iio_trigger_list_lock);
 
 	return 0;
 
+error_device_del:
+	device_del(&trig_info->dev);
 error_unregister_id:
 	ida_simple_remove(&iio_trigger_ida, trig_info->id);
 	return ret;

@@ -105,6 +114,18 @@ void iio_trigger_unregister(struct iio_trigger *trig_info)
 }
 EXPORT_SYMBOL(iio_trigger_unregister);
 
+/* Search for trigger by name, assuming iio_trigger_list_lock held */
+static struct iio_trigger *__iio_trigger_find_by_name(const char *name)
+{
+	struct iio_trigger *iter;
+
+	list_for_each_entry(iter, &iio_trigger_list, list)
+		if (!strcmp(iter->name, name))
+			return iter;
+
+	return NULL;
+}
+
 static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 						    size_t len)
 {

Quoted 6 lines · Crestez Dan Leonard

The trigger name is documented as unique but drivers are currently allowed to register triggers with duplicate names. This should be considered a bug since it makes the 'current_trigger' interface unusable.

Signed-off-by Crestez Dan Leonard <[email protected]>

This feels like the right approach to my mind (and should have been there all along - oops).

However, we do need to avoid breaking userspace. It's ugly but for those 3 drivers can we assume that using more than one on a board was impossible before this series and as such play a slight game in which we don't change the trigger name they are exporting, unless that name is already in use?

It's ugly but it gets us the nicest solution for all drivers for a bit of ugly in 3 of them...

Quoted 10 lines · Jonathan Cameron

Quoted 6 lines · Crestez Dan Leonard

The trigger name is documented as unique but drivers are currently allowed to register triggers with duplicate names. This should be considered a bug since it makes the 'current_trigger' interface unusable.

Signed-off-by Crestez Dan Leonard <[email protected]>

This feels like the right approach to my mind (and should have been there all along - oops).

Quoted 7 lines

However, we do need to avoid breaking userspace. It's ugly but for those 3 drivers can we assume that using more than one on a board was impossible before this series and as such play a slight game in which we don't change the trigger name they are exporting, unless that name is already in use?

It's ugly but it gets us the nicest solution for all drivers for a bit of ugly in 3 of them...

How would that look like? I guess I could handle -EEXIST from iio_trigger_register and try again with another name? Unfortunately the name is initialized at alloc time while uniqueness can only be checked at register time. This would require some refactoring in drivers for devices I don't have.

An alternative would be to just submit patches 4/5 and only give a warning when non-unique trigger names are used. After all, iio device names are not unique, the easy way would be to give up on this guarantee for trigger names as well.

Quoted 25 lines · Crestez Dan Leonard

Quoted 10 lines · Jonathan Cameron

Quoted 6 lines · Crestez Dan Leonard

The trigger name is documented as unique but drivers are currently allowed to register triggers with duplicate names. This should be considered a bug since it makes the 'current_trigger' interface unusable.

Signed-off-by Crestez Dan Leonard <[email protected]>

This feels like the right approach to my mind (and should have been there all along - oops).

Quoted 7 lines

However, we do need to avoid breaking userspace. It's ugly but for those 3 drivers can we assume that using more than one on a board was impossible before this series and as such play a slight game in which we don't change the trigger name they are exporting, unless that name is already in use?

It's ugly but it gets us the nicest solution for all drivers for a bit of ugly in 3 of them...

How would that look like? I guess I could handle -EEXIST from iio_trigger_register and try again with another name? Unfortunately the name is initialized at alloc time while uniqueness can only be checked at register time. This would require some refactoring in drivers for devices I don't have.

Quoted 5 lines

An alternative would be to just submit patches 4/5 and only give a warning when non-unique trigger names are used. After all, iio device names are not unique, the easy way would be to give up on this guarantee for trigger names as well.

I'd say apply this patch keep things as they are in the drivers and if somebody creates a board with more than one of those devices let them come up with a fix.

--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html

IIO documents that trigger names are unique but does not actually guarantee this. You can easily create a software trigger with a duplicate name if you enable CONFIG_IIO_HRTIMER_TRIGGER:

	mkdir /sys/kernel/config/iio/triggers/hrtimer/\
		`cat /sys/bus/iio/devices/trigger0/name`

You can also get in this situation if you connect two identical st_sensors.

My attempt to fix this is by adding a new 'current_trigger_id' ABI which is a numeric ID (X from triggerX) rather than a non-unique string. I tested that this works as expected when connecting two LIS3DH to the same system. This is in patches 4,5.

In theory the current_trigger ABI could be overloaded to looks for something matching "trigger[0-9]+" but this would be nastier. There would be a need to prevent registering triggers that match that expression in order to prevent stuff like:

mkdir /sys/kernel/config/iio/triggers/hrtimer/trigger1

Such an overload wouldn't work on read and make it impossible to unambigiously determine the currently selected trigger.

Patch 6 disallows registering duplicate trigger names. This makes drivers which currently do that break at probe time.

Patch 7 attempts to ensure that all drivers include indio_dev->id when calling iio_trigger_alloc. This obviously changes trigger names.

Either 4,5 or 6,7 fix this issue, but 4,5 causes fewer compat issues.

Patches 1,2,3 are just minor features in tools/generic_buffer. They supersede the v2 I posted earlier:

	https://www.spinics.net/lists/linux-iio/msg24867.html

Crestez Dan Leonard (7):
iio: generic_buffer: Cleanup when receiving signals
iio: generic_buffer: Add --device-num option
iio: generic_buffer: Add --trigger-num option
iio: Add current_trigger_id alternative
iio: generic_buffer: Use current_trigger_id
iio: Refuse to register triggers with duplicate names
iio: Make trigger names unique

 Documentation/ABI/testing/sysfs-bus-iio            |   9 +
 Documentation/DocBook/iio.tmpl                     |   4 +-
 drivers/iio/adc/max1027.c                          |   4 +-
 drivers/iio/common/st_sensors/st_sensors_trigger.c |   2 +-
 drivers/iio/industrialio-trigger.c                 | 136 ++++++++---
 drivers/iio/light/gp2ap020a00f.c                   |   4 +-
 tools/iio/generic_buffer.c                         | 269 ++++++++++++++-------
 7 files changed, 309 insertions(+), 119 deletions(-)