iio: iio_generic_buffer: Add --device-num option

This makes it possible to distinguish between iio devices with the same
name.
Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

tools/iio/iio_generic_buffer.c

@@ -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 @@ int main(int argc, char **argv)
 	}
 	free(channels);
 	free(trigger_name);
+	free(device_name);
 	free(dev_dir_name);
 
 	return ret;