Introduce v4l2-get-device tool

This tool allows to find a device by driver name, this is useful for scripts to be written in a generic way.

Usage:

v4l2-get-device -d uvcvideo -c V4L2_CAP_VIDEO_CAPTURE /dev/video0
/dev/video2

Signed-off-by Ezequiel Garcia <[email protected]>

---
 configure.ac                            |   1 +
 utils/Makefile.am                       |   1 +
 utils/v4l2-get-device/.gitignore        |   1 +
 utils/v4l2-get-device/Makefile.am       |   4 +
 utils/v4l2-get-device/v4l2-get-device.c | 147 ++++++++++++++++++++++++
 v4l-utils.spec.in                       |   1 +
 6 files changed, 155 insertions(+)
 create mode 100644 utils/v4l2-get-device/.gitignore
 create mode 100644 utils/v4l2-get-device/Makefile.am
 create mode 100644 utils/v4l2-get-device/v4l2-get-device.c

configure.ac +1 -0

index 5cc34c248fbf..918cb59704b9 100644
@@ -31,6 +31,7 @@ AC_CONFIG_FILES([Makefile
 	utils/v4l2-compliance/Makefile
 	utils/v4l2-ctl/Makefile
 	utils/v4l2-dbg/Makefile
+	utils/v4l2-get-device/Makefile
 	utils/v4l2-sysfs-path/Makefile
 	utils/qv4l2/Makefile
 	utils/cec-ctl/Makefile

utils/Makefile.am +1 -0

index 2d5070288c13..2b2b27107d13 100644
@@ -9,6 +9,7 @@ SUBDIRS = \
 	v4l2-compliance \
 	v4l2-ctl \
 	v4l2-dbg \
+	v4l2-get-device \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \

utils/v4l2-get-device/.gitignore new file +1 -0

new file mode 100644
index 000000000000..b222144c9f4e
@@ -0,0 +1 @@
+v4l2-get-device

utils/v4l2-get-device/Makefile.am new file +4 -0

new file mode 100644
index 000000000000..2e5a6e0ba32f
@@ -0,0 +1,4 @@
+bin_PROGRAMS = v4l2-get-device
+v4l2_get_device_SOURCES = v4l2-get-device.c
+v4l2_get_device_LDADD = ../libmedia_dev/libmedia_dev.la
+v4l2_get_device_LDFLAGS = $(ARGP_LIBS)

utils/v4l2-get-device/v4l2-get-device.c new file +44 -0

new file mode 100644
index 000000000000..f9cc323b7057
@@ -0,0 +1,147 @@
+/*
+ * Copyright © 2018 Collabora, Ltd.
+ *
+ * Based on v4l2-sysfs-path by Mauro Carvalho Chehab:
+ *
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <argp.h>
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/unistd.h>
+
+#include <linux/videodev2.h>
+
+#include "../libmedia_dev/get_media_devices.h"
+
+const char *argp_program_version = "v4l2-get-device " V4L_UTILS_VERSION;

utils/v4l2-get-device/v4l2-get-device.c new file +10 -0

+	{ 0 }
+};
+
+static unsigned int parse_capabilities(const char *arg)
+{
+	char *s, *str = strdup(arg);
+	unsigned int caps = 0;
+
+	s = strtok (str,",");
+	while (s != NULL) {

utils/v4l2-get-device/v4l2-get-device.c new file +29 -0

+		s = strtok (NULL, ",");
+	}
+	free(str);
+	return caps;
+}
+
+static error_t parse_opt(int k, char *arg, struct argp_state *state)
+{
+	struct args *args = state->input;
+
+	switch (k) {
+	case 'd':
+		args->driver = arg;
+		break;
+	case 'c':
+		args->device_caps = parse_capabilities(arg);
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static struct argp argp = {
+	.options = options,
+	.parser = parse_opt,
+};
+
+int main(int argc, char *argv[])

utils/v4l2-get-device/v4l2-get-device.c new file +34 -0

+
+	vid = NULL;
+	do {
+		struct v4l2_capability cap;
+		char devnode[64];
+		int ret;
+		int fd;
+
+		vid = get_associated_device(md, vid, MEDIA_V4L_VIDEO,
+					    NULL, NONE);
+		if (!vid)
+			break;
+		snprintf(devnode, 64, "/dev/%s", vid);
+		fd = open(devnode, O_RDWR);
+		if (fd < 0)
+			continue;
+
+		memset(&cap, 0, sizeof cap);
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+		if (ret) {
+			close(fd);
+			continue;
+		}
+		close(fd);
+
+		if (strncmp(args.driver, (char *)cap.driver, sizeof(cap.driver)))
+			continue;
+		if (args.device_caps && (args.device_caps & cap.device_caps) != args.device_caps)
+			continue;
+		fprintf(stdout, "%s\n", devnode);
+	} while (vid);
+	free_media_devices(md);
+	return 0;
+}

v4l-utils.spec.in +0 -0

index 67bdca57ae92..ab15286b039b 100644

Quoted 2 lines · Ezequiel Garcia

This tool allows to find a device by driver name, this is useful for scripts to be written in a generic way.

Why not add support for this to v4l2-sysfs-path? And improve it at the same time (swradio devices do not show up when I run v4l2-sysfs-path, I also suspect v4l-touch devices aren't recognized. Ditto for media devices.

Quoted 114 lines

Usage:

v4l2-get-device -d uvcvideo -c V4L2_CAP_VIDEO_CAPTURE /dev/video0
/dev/video2

Signed-off-by Ezequiel Garcia <[email protected]>

---
 configure.ac                            |   1 +
 utils/Makefile.am                       |   1 +
 utils/v4l2-get-device/.gitignore        |   1 +
 utils/v4l2-get-device/Makefile.am       |   4 +
 utils/v4l2-get-device/v4l2-get-device.c | 147 ++++++++++++++++++++++++
 v4l-utils.spec.in                       |   1 +
 6 files changed, 155 insertions(+)
 create mode 100644 utils/v4l2-get-device/.gitignore
 create mode 100644 utils/v4l2-get-device/Makefile.am
 create mode 100644 utils/v4l2-get-device/v4l2-get-device.c

configure.ac +1 -0

index 5cc34c248fbf..918cb59704b9 100644
@@ -31,6 +31,7 @@ AC_CONFIG_FILES([Makefile
 	utils/v4l2-compliance/Makefile
 	utils/v4l2-ctl/Makefile
 	utils/v4l2-dbg/Makefile
+	utils/v4l2-get-device/Makefile
 	utils/v4l2-sysfs-path/Makefile
 	utils/qv4l2/Makefile
 	utils/cec-ctl/Makefile

utils/Makefile.am +1 -0

index 2d5070288c13..2b2b27107d13 100644
@@ -9,6 +9,7 @@ SUBDIRS = \
 	v4l2-compliance \
 	v4l2-ctl \
 	v4l2-dbg \
+	v4l2-get-device \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \

utils/v4l2-get-device/.gitignore new file +1 -0

new file mode 100644
index 000000000000..b222144c9f4e
@@ -0,0 +1 @@
+v4l2-get-device

utils/v4l2-get-device/Makefile.am new file +4 -0

new file mode 100644
index 000000000000..2e5a6e0ba32f
@@ -0,0 +1,4 @@
+bin_PROGRAMS = v4l2-get-device
+v4l2_get_device_SOURCES = v4l2-get-device.c
+v4l2_get_device_LDADD = ../libmedia_dev/libmedia_dev.la
+v4l2_get_device_LDFLAGS = $(ARGP_LIBS)

utils/v4l2-get-device/v4l2-get-device.c new file +48 -0

new file mode 100644
index 000000000000..f9cc323b7057
@@ -0,0 +1,147 @@
+/*
+ * Copyright © 2018 Collabora, Ltd.
+ *
+ * Based on v4l2-sysfs-path by Mauro Carvalho Chehab:
+ *
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <argp.h>
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/unistd.h>
+
+#include <linux/videodev2.h>
+
+#include "../libmedia_dev/get_media_devices.h"
+
+const char *argp_program_version = "v4l2-get-device " V4L_UTILS_VERSION;
+const char *argp_program_bug_address = "Ezequiel Garcia <[email protected]>";
+
+struct args {
+	const char *driver;

utils/v4l2-get-device/v4l2-get-device.c line 54

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+	unsigned int device_caps;
+};
+
+static const struct argp_option options[] = {
+	{"driver", 'd', "DRIVER", 0, "device driver name", 0},
+	{"v4l2-device-caps", 'c', "CAPS", 0, "v4l2 device capabilities", 0},

I'd like a bus-info option as well, if possible.

Quoted 15 lines

utils/v4l2-get-device/v4l2-get-device.c new file +15 -0

+	{ 0 }
+};
+
+static unsigned int parse_capabilities(const char *arg)
+{
+	char *s, *str = strdup(arg);
+	unsigned int caps = 0;
+
+	s = strtok (str,",");
+	while (s != NULL) {
+		if (!strcmp(s, "V4L2_CAP_VIDEO_CAPTURE"))
+			caps |= V4L2_CAP_VIDEO_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OUTPUT"))
+			caps |= V4L2_CAP_VIDEO_OUTPUT;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OVERLAY"))

utils/v4l2-get-device/v4l2-get-device.c line 74

Quoted 5 lines

utils/v4l2-get-device/v4l2-get-device.c new file +5 -0

+			caps |= V4L2_CAP_VIDEO_OVERLAY;
+		else if (!strcmp(s, "V4L2_CAP_VBI_CAPTURE"))
+			caps |= V4L2_CAP_VBI_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VBI_OUTPUT"))
+			caps |= V4L2_CAP_VBI_OUTPUT;

Let's support all CAPS here. I'd also drop the V4L2_CAP_ prefix (or make it optional) and make the strcmp case-insensitive to ease typing.

Quoted 33 lines

utils/v4l2-get-device/v4l2-get-device.c new file +33 -0

+		s = strtok (NULL, ",");
+	}
+	free(str);
+	return caps;
+}
+
+static error_t parse_opt(int k, char *arg, struct argp_state *state)
+{
+	struct args *args = state->input;
+
+	switch (k) {
+	case 'd':
+		args->driver = arg;
+		break;
+	case 'c':
+		args->device_caps = parse_capabilities(arg);
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static struct argp argp = {
+	.options = options,
+	.parser = parse_opt,
+};
+
+int main(int argc, char *argv[])
+{
+	const char *vid;
+	struct args args;
+	void *md;

utils/v4l2-get-device/v4l2-get-device.c line 113

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+
+	args.driver = NULL;
+	args.device_caps = 0;
+	argp_parse(&argp, argc, argv, 0, 0, &args);
+
+	md = discover_media_devices();

I never really liked this. My main problem is that it doesn't know about media devices.

In my view it should look for media devices first, query them and get all the device nodes referenced in the topology, and then fall back to the old method to discover any remaining device nodes for drivers that do not create a media device.

You need media device support anyway since you also want to be able to query the media device for a specific driver and find the device node for a specific entity.

Quoted 40 lines

utils/v4l2-get-device/v4l2-get-device.c new file +34 -0

+
+	vid = NULL;
+	do {
+		struct v4l2_capability cap;
+		char devnode[64];
+		int ret;
+		int fd;
+
+		vid = get_associated_device(md, vid, MEDIA_V4L_VIDEO,
+					    NULL, NONE);
+		if (!vid)
+			break;
+		snprintf(devnode, 64, "/dev/%s", vid);
+		fd = open(devnode, O_RDWR);
+		if (fd < 0)
+			continue;
+
+		memset(&cap, 0, sizeof cap);
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+		if (ret) {
+			close(fd);
+			continue;
+		}
+		close(fd);
+
+		if (strncmp(args.driver, (char *)cap.driver, sizeof(cap.driver)))
+			continue;
+		if (args.device_caps && (args.device_caps & cap.device_caps) != args.device_caps)
+			continue;
+		fprintf(stdout, "%s\n", devnode);
+	} while (vid);
+	free_media_devices(md);
+	return 0;
+}

v4l-utils.spec.in +0 -0

index 67bdca57ae92..ab15286b039b 100644

v4l-utils.spec.in gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || : · line 165

Quoted 7 lines

v4l-utils.spec.in +1 -0

@@ -159,6 +159,7 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 %{_bindir}/ivtv-ctl
 %{_bindir}/v4l2-ctl
 %{_bindir}/v4l2-sysfs-path
+%{_bindir}/v4l2-get-device
 %{_mandir}/man1/ir-keytable.1*
 %{_mandir}/man1/ir-ctl.1*
 

Regards,

Hans

Quoted 4 lines · Hans Verkuil

Quoted 2 lines · Ezequiel Garcia

This tool allows to find a device by driver name, this is useful for scripts to be written in a generic way.

Quoted 4 lines

Why not add support for this to v4l2-sysfs-path? And improve it at the same time (swradio devices do not show up when I run v4l2-sysfs-path, I also suspect v4l-touch devices aren't recognized. Ditto for media devices.

I can add the functionality to v4l2-sysfs-path, and we can document the rest in some TODO list, as I don't think we need to get everything solved right now :-)

Quoted 115 lines

Quoted 115 lines

Usage:

v4l2-get-device -d uvcvideo -c V4L2_CAP_VIDEO_CAPTURE /dev/video0
/dev/video2

Signed-off-by Ezequiel Garcia <[email protected]>

---
 configure.ac                            |   1 +
 utils/Makefile.am                       |   1 +
 utils/v4l2-get-device/.gitignore        |   1 +
 utils/v4l2-get-device/Makefile.am       |   4 +
 utils/v4l2-get-device/v4l2-get-device.c | 147 ++++++++++++++++++++++++
 v4l-utils.spec.in                       |   1 +
 6 files changed, 155 insertions(+)
 create mode 100644 utils/v4l2-get-device/.gitignore
 create mode 100644 utils/v4l2-get-device/Makefile.am
 create mode 100644 utils/v4l2-get-device/v4l2-get-device.c

configure.ac +1 -0

index 5cc34c248fbf..918cb59704b9 100644
@@ -31,6 +31,7 @@ AC_CONFIG_FILES([Makefile
 	utils/v4l2-compliance/Makefile
 	utils/v4l2-ctl/Makefile
 	utils/v4l2-dbg/Makefile
+	utils/v4l2-get-device/Makefile
 	utils/v4l2-sysfs-path/Makefile
 	utils/qv4l2/Makefile
 	utils/cec-ctl/Makefile

utils/Makefile.am +1 -0

index 2d5070288c13..2b2b27107d13 100644
@@ -9,6 +9,7 @@ SUBDIRS = \
 	v4l2-compliance \
 	v4l2-ctl \
 	v4l2-dbg \
+	v4l2-get-device \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \

utils/v4l2-get-device/.gitignore new file +1 -0

new file mode 100644
index 000000000000..b222144c9f4e
@@ -0,0 +1 @@
+v4l2-get-device

utils/v4l2-get-device/Makefile.am new file +4 -0

new file mode 100644
index 000000000000..2e5a6e0ba32f
@@ -0,0 +1,4 @@
+bin_PROGRAMS = v4l2-get-device
+v4l2_get_device_SOURCES = v4l2-get-device.c
+v4l2_get_device_LDADD = ../libmedia_dev/libmedia_dev.la
+v4l2_get_device_LDFLAGS = $(ARGP_LIBS)

utils/v4l2-get-device/v4l2-get-device.c new file +48 -0

new file mode 100644
index 000000000000..f9cc323b7057
@@ -0,0 +1,147 @@
+/*
+ * Copyright © 2018 Collabora, Ltd.
+ *
+ * Based on v4l2-sysfs-path by Mauro Carvalho Chehab:
+ *
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <argp.h>
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/unistd.h>
+
+#include <linux/videodev2.h>
+
+#include "../libmedia_dev/get_media_devices.h"
+
+const char *argp_program_version = "v4l2-get-device " V4L_UTILS_VERSION;
+const char *argp_program_bug_address = "Ezequiel Garcia <[email protected]>";
+
+struct args {
+	const char *driver;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 54

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+	unsigned int device_caps;
+};
+
+static const struct argp_option options[] = {
+	{"driver", 'd', "DRIVER", 0, "device driver name", 0},
+	{"v4l2-device-caps", 'c', "CAPS", 0, "v4l2 device capabilities", 0},

I'd like a bus-info option as well, if possible.

Guess that works.

Quoted 15 lines

Quoted 15 lines

utils/v4l2-get-device/v4l2-get-device.c new file +15 -0

+	{ 0 }
+};
+
+static unsigned int parse_capabilities(const char *arg)
+{
+	char *s, *str = strdup(arg);
+	unsigned int caps = 0;
+
+	s = strtok (str,",");
+	while (s != NULL) {
+		if (!strcmp(s, "V4L2_CAP_VIDEO_CAPTURE"))
+			caps |= V4L2_CAP_VIDEO_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OUTPUT"))
+			caps |= V4L2_CAP_VIDEO_OUTPUT;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OVERLAY"))

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 74

Quoted 5 lines

utils/v4l2-get-device/v4l2-get-device.c new file +5 -0

+			caps |= V4L2_CAP_VIDEO_OVERLAY;
+		else if (!strcmp(s, "V4L2_CAP_VBI_CAPTURE"))
+			caps |= V4L2_CAP_VBI_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VBI_OUTPUT"))
+			caps |= V4L2_CAP_VBI_OUTPUT;

Let's support all CAPS here. I'd also drop the V4L2_CAP_ prefix (or make it optional) and make the strcmp case-insensitive to ease typing.

OK.

Quoted 33 lines

Quoted 33 lines

utils/v4l2-get-device/v4l2-get-device.c new file +33 -0

+		s = strtok (NULL, ",");
+	}
+	free(str);
+	return caps;
+}
+
+static error_t parse_opt(int k, char *arg, struct argp_state *state)
+{
+	struct args *args = state->input;
+
+	switch (k) {
+	case 'd':
+		args->driver = arg;
+		break;
+	case 'c':
+		args->device_caps = parse_capabilities(arg);
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static struct argp argp = {
+	.options = options,
+	.parser = parse_opt,
+};
+
+int main(int argc, char *argv[])
+{
+	const char *vid;
+	struct args args;
+	void *md;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 113

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+
+	args.driver = NULL;
+	args.device_caps = 0;
+	argp_parse(&argp, argc, argv, 0, 0, &args);
+
+	md = discover_media_devices();

I never really liked this. My main problem is that it doesn't know about media devices.

Sorry, not sure what you don't really like?

The discover_media_devices() is maybe not the best API, but it's what v4l2-sysfs-path uses, and it seemed to fit what we need as a first step (to find v4l2 devices).

Perhaps we can use this for now and pospone improving the discovery library?

Quoted 8 lines

In my view it should look for media devices first, query them and get all the device nodes referenced in the topology, and then fall back to the old method to discover any remaining device nodes for drivers that do not create a media device.

You need media device support anyway since you also want to be able to query the media device for a specific driver and find the device node for a specific entity.

I've been thinking about this (since I started with http://git.ideasonboard.org/media-enum.git),
but to be honest, I failed to see why I would want to query media devices.

Let's say we want to find a H264 decoder, I don't think the topology is be of much use, is it?

In any case, I think this is part of a bigger discussion, would you consider merging v4l discovery for now?

Quoted 51 lines

Quoted 40 lines

utils/v4l2-get-device/v4l2-get-device.c new file +34 -0

+
+	vid = NULL;
+	do {
+		struct v4l2_capability cap;
+		char devnode[64];
+		int ret;
+		int fd;
+
+		vid = get_associated_device(md, vid, MEDIA_V4L_VIDEO,
+					    NULL, NONE);
+		if (!vid)
+			break;
+		snprintf(devnode, 64, "/dev/%s", vid);
+		fd = open(devnode, O_RDWR);
+		if (fd < 0)
+			continue;
+
+		memset(&cap, 0, sizeof cap);
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+		if (ret) {
+			close(fd);
+			continue;
+		}
+		close(fd);
+
+		if (strncmp(args.driver, (char *)cap.driver, sizeof(cap.driver)))
+			continue;
+		if (args.device_caps && (args.device_caps & cap.device_caps) != args.device_caps)
+			continue;
+		fprintf(stdout, "%s\n", devnode);
+	} while (vid);
+	free_media_devices(md);
+	return 0;
+}

v4l-utils.spec.in +0 -0

index 67bdca57ae92..ab15286b039b 100644

v4l-utils.spec.in gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || : · line 165

Quoted 7 lines

v4l-utils.spec.in +1 -0

@@ -159,6 +159,7 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 %{_bindir}/ivtv-ctl
 %{_bindir}/v4l2-ctl
 %{_bindir}/v4l2-sysfs-path
+%{_bindir}/v4l2-get-device
 %{_mandir}/man1/ir-keytable.1*
 %{_mandir}/man1/ir-ctl.1*
 

Regards,

Hans

Quoted 10 lines · Ezequiel Garcia

Quoted 8 lines · Hans Verkuil

Quoted 2 lines · Ezequiel Garcia

This tool allows to find a device by driver name, this is useful for scripts to be written in a generic way.

Why not add support for this to v4l2-sysfs-path? And improve it at the same time (swradio devices do not show up when I run v4l2-sysfs-path, I also suspect v4l-touch devices aren't recognized. Ditto for media devices.

Quoted 3 lines

I can add the functionality to v4l2-sysfs-path, and we can document the rest in some TODO list, as I don't think we need to get everything solved right now :-)

I agree with that.

Quoted 196 lines

Quoted 114 lines

Quoted 114 lines

Usage:

v4l2-get-device -d uvcvideo -c V4L2_CAP_VIDEO_CAPTURE /dev/video0
/dev/video2

Signed-off-by Ezequiel Garcia <[email protected]>

---
 configure.ac                            |   1 +
 utils/Makefile.am                       |   1 +
 utils/v4l2-get-device/.gitignore        |   1 +
 utils/v4l2-get-device/Makefile.am       |   4 +
 utils/v4l2-get-device/v4l2-get-device.c | 147 ++++++++++++++++++++++++
 v4l-utils.spec.in                       |   1 +
 6 files changed, 155 insertions(+)
 create mode 100644 utils/v4l2-get-device/.gitignore
 create mode 100644 utils/v4l2-get-device/Makefile.am
 create mode 100644 utils/v4l2-get-device/v4l2-get-device.c

configure.ac +1 -0

index 5cc34c248fbf..918cb59704b9 100644
@@ -31,6 +31,7 @@ AC_CONFIG_FILES([Makefile
 	utils/v4l2-compliance/Makefile
 	utils/v4l2-ctl/Makefile
 	utils/v4l2-dbg/Makefile
+	utils/v4l2-get-device/Makefile
 	utils/v4l2-sysfs-path/Makefile
 	utils/qv4l2/Makefile
 	utils/cec-ctl/Makefile

utils/Makefile.am +1 -0

index 2d5070288c13..2b2b27107d13 100644
@@ -9,6 +9,7 @@ SUBDIRS = \
 	v4l2-compliance \
 	v4l2-ctl \
 	v4l2-dbg \
+	v4l2-get-device \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \

utils/v4l2-get-device/.gitignore new file +1 -0

new file mode 100644
index 000000000000..b222144c9f4e
@@ -0,0 +1 @@
+v4l2-get-device

utils/v4l2-get-device/Makefile.am new file +4 -0

new file mode 100644
index 000000000000..2e5a6e0ba32f
@@ -0,0 +1,4 @@
+bin_PROGRAMS = v4l2-get-device
+v4l2_get_device_SOURCES = v4l2-get-device.c
+v4l2_get_device_LDADD = ../libmedia_dev/libmedia_dev.la
+v4l2_get_device_LDFLAGS = $(ARGP_LIBS)

utils/v4l2-get-device/v4l2-get-device.c new file +48 -0

new file mode 100644
index 000000000000..f9cc323b7057
@@ -0,0 +1,147 @@
+/*
+ * Copyright © 2018 Collabora, Ltd.
+ *
+ * Based on v4l2-sysfs-path by Mauro Carvalho Chehab:
+ *
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <argp.h>
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/unistd.h>
+
+#include <linux/videodev2.h>
+
+#include "../libmedia_dev/get_media_devices.h"
+
+const char *argp_program_version = "v4l2-get-device " V4L_UTILS_VERSION;
+const char *argp_program_bug_address = "Ezequiel Garcia <[email protected]>";
+
+struct args {
+	const char *driver;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 54

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+	unsigned int device_caps;
+};
+
+static const struct argp_option options[] = {
+	{"driver", 'd', "DRIVER", 0, "device driver name", 0},
+	{"v4l2-device-caps", 'c', "CAPS", 0, "v4l2 device capabilities", 0},

I'd like a bus-info option as well, if possible.

Guess that works.

Quoted 15 lines

Quoted 15 lines

utils/v4l2-get-device/v4l2-get-device.c new file +15 -0

+	{ 0 }
+};
+
+static unsigned int parse_capabilities(const char *arg)
+{
+	char *s, *str = strdup(arg);
+	unsigned int caps = 0;
+
+	s = strtok (str,",");
+	while (s != NULL) {
+		if (!strcmp(s, "V4L2_CAP_VIDEO_CAPTURE"))
+			caps |= V4L2_CAP_VIDEO_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OUTPUT"))
+			caps |= V4L2_CAP_VIDEO_OUTPUT;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OVERLAY"))

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 74

Quoted 5 lines

utils/v4l2-get-device/v4l2-get-device.c new file +5 -0

+			caps |= V4L2_CAP_VIDEO_OVERLAY;
+		else if (!strcmp(s, "V4L2_CAP_VBI_CAPTURE"))
+			caps |= V4L2_CAP_VBI_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VBI_OUTPUT"))
+			caps |= V4L2_CAP_VBI_OUTPUT;

Let's support all CAPS here. I'd also drop the V4L2_CAP_ prefix (or make it optional) and make the strcmp case-insensitive to ease typing.

OK.

Quoted 33 lines

Quoted 33 lines

utils/v4l2-get-device/v4l2-get-device.c new file +33 -0

+		s = strtok (NULL, ",");
+	}
+	free(str);
+	return caps;
+}
+
+static error_t parse_opt(int k, char *arg, struct argp_state *state)
+{
+	struct args *args = state->input;
+
+	switch (k) {
+	case 'd':
+		args->driver = arg;
+		break;
+	case 'c':
+		args->device_caps = parse_capabilities(arg);
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static struct argp argp = {
+	.options = options,
+	.parser = parse_opt,
+};
+
+int main(int argc, char *argv[])
+{
+	const char *vid;
+	struct args args;
+	void *md;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 113

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+
+	args.driver = NULL;
+	args.device_caps = 0;
+	argp_parse(&argp, argc, argv, 0, 0, &args);
+
+	md = discover_media_devices();

I never really liked this. My main problem is that it doesn't know about media devices.

Quoted 6 lines

Sorry, not sure what you don't really like?

The discover_media_devices() is maybe not the best API, but it's what v4l2-sysfs-path uses, and it seemed to fit what we need as a first step (to find v4l2 devices).

Perhaps we can use this for now and pospone improving the discovery library?

Yes, that can be postponed (I should have been clear about that, sorry).

Quoted 8 lines

Quoted 7 lines

In my view it should look for media devices first, query them and get all the device nodes referenced in the topology, and then fall back to the old method to discover any remaining device nodes for drivers that do not create a media device.

You need media device support anyway since you also want to be able to query the media device for a specific driver and find the device node for a specific entity.

Quoted 5 lines

I've been thinking about this (since I started with http://git.ideasonboard.org/media-enum.git),
but to be honest, I failed to see why I would want to query media devices.

Let's say we want to find a H264 decoder, I don't think the topology is be of much use, is it?

Not for codecs, but this should become a generic utility that you can also use to find e.g. v4l-subdev device nodes from a complex camera driver.

Regards,

Hans

Quoted 54 lines

In any case, I think this is part of a bigger discussion, would you consider merging v4l discovery for now?

Quoted 51 lines

Quoted 40 lines

utils/v4l2-get-device/v4l2-get-device.c new file +34 -0

+
+	vid = NULL;
+	do {
+		struct v4l2_capability cap;
+		char devnode[64];
+		int ret;
+		int fd;
+
+		vid = get_associated_device(md, vid, MEDIA_V4L_VIDEO,
+					    NULL, NONE);
+		if (!vid)
+			break;
+		snprintf(devnode, 64, "/dev/%s", vid);
+		fd = open(devnode, O_RDWR);
+		if (fd < 0)
+			continue;
+
+		memset(&cap, 0, sizeof cap);
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+		if (ret) {
+			close(fd);
+			continue;
+		}
+		close(fd);
+
+		if (strncmp(args.driver, (char *)cap.driver, sizeof(cap.driver)))
+			continue;
+		if (args.device_caps && (args.device_caps & cap.device_caps) != args.device_caps)
+			continue;
+		fprintf(stdout, "%s\n", devnode);
+	} while (vid);
+	free_media_devices(md);
+	return 0;
+}

v4l-utils.spec.in +0 -0

index 67bdca57ae92..ab15286b039b 100644

v4l-utils.spec.in gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || : · line 165

Quoted 7 lines

v4l-utils.spec.in +1 -0

@@ -159,6 +159,7 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 %{_bindir}/ivtv-ctl
 %{_bindir}/v4l2-ctl
 %{_bindir}/v4l2-sysfs-path
+%{_bindir}/v4l2-get-device
 %{_mandir}/man1/ir-keytable.1*
 %{_mandir}/man1/ir-ctl.1*
 

Regards,

Hans

Quoted 15 lines · Hans Verkuil

Quoted 13 lines · Ezequiel Garcia

Quoted 8 lines · Hans Verkuil

Quoted 2 lines · Ezequiel Garcia

This tool allows to find a device by driver name, this is useful for scripts to be written in a generic way.

Why not add support for this to v4l2-sysfs-path? And improve it at the same time (swradio devices do not show up when I run v4l2-sysfs-path, I also suspect v4l-touch devices aren't recognized. Ditto for media devices.

I can add the functionality to v4l2-sysfs-path, and we can document the rest in some TODO list, as I don't think we need to get everything solved right now :-)

Quoted 2 lines

I agree with that.

Great!

About adding it to v4l2-sysfs-path, is there any scenario where we'll want to use udev-based scanning instead of sysfs-based? Maybe we can rename the tool, and still install a v4l2-sysfs-path alias?

Quoted 214 lines

Quoted 197 lines

Quoted 115 lines

Quoted 115 lines

Usage:

v4l2-get-device -d uvcvideo -c V4L2_CAP_VIDEO_CAPTURE /dev/video0
/dev/video2

Signed-off-by Ezequiel Garcia <[email protected]>

---
 configure.ac                            |   1 +
 utils/Makefile.am                       |   1 +
 utils/v4l2-get-device/.gitignore        |   1 +
 utils/v4l2-get-device/Makefile.am       |   4 +
 utils/v4l2-get-device/v4l2-get-device.c | 147 ++++++++++++++++++++++++
 v4l-utils.spec.in                       |   1 +
 6 files changed, 155 insertions(+)
 create mode 100644 utils/v4l2-get-device/.gitignore
 create mode 100644 utils/v4l2-get-device/Makefile.am
 create mode 100644 utils/v4l2-get-device/v4l2-get-device.c

configure.ac +1 -0

index 5cc34c248fbf..918cb59704b9 100644
@@ -31,6 +31,7 @@ AC_CONFIG_FILES([Makefile
 	utils/v4l2-compliance/Makefile
 	utils/v4l2-ctl/Makefile
 	utils/v4l2-dbg/Makefile
+	utils/v4l2-get-device/Makefile
 	utils/v4l2-sysfs-path/Makefile
 	utils/qv4l2/Makefile
 	utils/cec-ctl/Makefile

utils/Makefile.am +1 -0

index 2d5070288c13..2b2b27107d13 100644
@@ -9,6 +9,7 @@ SUBDIRS = \
 	v4l2-compliance \
 	v4l2-ctl \
 	v4l2-dbg \
+	v4l2-get-device \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \

utils/v4l2-get-device/.gitignore new file +1 -0

new file mode 100644
index 000000000000..b222144c9f4e
@@ -0,0 +1 @@
+v4l2-get-device

utils/v4l2-get-device/Makefile.am new file +4 -0

new file mode 100644
index 000000000000..2e5a6e0ba32f
@@ -0,0 +1,4 @@
+bin_PROGRAMS = v4l2-get-device
+v4l2_get_device_SOURCES = v4l2-get-device.c
+v4l2_get_device_LDADD = ../libmedia_dev/libmedia_dev.la
+v4l2_get_device_LDFLAGS = $(ARGP_LIBS)

utils/v4l2-get-device/v4l2-get-device.c new file +48 -0

new file mode 100644
index 000000000000..f9cc323b7057
@@ -0,0 +1,147 @@
+/*
+ * Copyright © 2018 Collabora, Ltd.
+ *
+ * Based on v4l2-sysfs-path by Mauro Carvalho Chehab:
+ *
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <argp.h>
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/unistd.h>
+
+#include <linux/videodev2.h>
+
+#include "../libmedia_dev/get_media_devices.h"
+
+const char *argp_program_version = "v4l2-get-device " V4L_UTILS_VERSION;
+const char *argp_program_bug_address = "Ezequiel Garcia <[email protected]>";
+
+struct args {
+	const char *driver;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 54

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+	unsigned int device_caps;
+};
+
+static const struct argp_option options[] = {
+	{"driver", 'd', "DRIVER", 0, "device driver name", 0},
+	{"v4l2-device-caps", 'c', "CAPS", 0, "v4l2 device capabilities", 0},

I'd like a bus-info option as well, if possible.

Guess that works.

Quoted 15 lines

Quoted 15 lines

utils/v4l2-get-device/v4l2-get-device.c new file +15 -0

+	{ 0 }
+};
+
+static unsigned int parse_capabilities(const char *arg)
+{
+	char *s, *str = strdup(arg);
+	unsigned int caps = 0;
+
+	s = strtok (str,",");
+	while (s != NULL) {
+		if (!strcmp(s, "V4L2_CAP_VIDEO_CAPTURE"))
+			caps |= V4L2_CAP_VIDEO_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OUTPUT"))
+			caps |= V4L2_CAP_VIDEO_OUTPUT;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OVERLAY"))

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 74

Quoted 5 lines

utils/v4l2-get-device/v4l2-get-device.c new file +5 -0

+			caps |= V4L2_CAP_VIDEO_OVERLAY;
+		else if (!strcmp(s, "V4L2_CAP_VBI_CAPTURE"))
+			caps |= V4L2_CAP_VBI_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VBI_OUTPUT"))
+			caps |= V4L2_CAP_VBI_OUTPUT;

Let's support all CAPS here. I'd also drop the V4L2_CAP_ prefix (or make it optional) and make the strcmp case-insensitive to ease typing.

OK.

Quoted 33 lines

Quoted 33 lines

utils/v4l2-get-device/v4l2-get-device.c new file +33 -0

+		s = strtok (NULL, ",");
+	}
+	free(str);
+	return caps;
+}
+
+static error_t parse_opt(int k, char *arg, struct argp_state *state)
+{
+	struct args *args = state->input;
+
+	switch (k) {
+	case 'd':
+		args->driver = arg;
+		break;
+	case 'c':
+		args->device_caps = parse_capabilities(arg);
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static struct argp argp = {
+	.options = options,
+	.parser = parse_opt,
+};
+
+int main(int argc, char *argv[])
+{
+	const char *vid;
+	struct args args;
+	void *md;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 113

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+
+	args.driver = NULL;
+	args.device_caps = 0;
+	argp_parse(&argp, argc, argv, 0, 0, &args);
+
+	md = discover_media_devices();

I never really liked this. My main problem is that it doesn't know about media devices.

Quoted 6 lines

Sorry, not sure what you don't really like?

The discover_media_devices() is maybe not the best API, but it's what v4l2-sysfs-path uses, and it seemed to fit what we need as a first step (to find v4l2 devices).

Perhaps we can use this for now and pospone improving the discovery library?

Yes, that can be postponed (I should have been clear about that, sorry).

Quoted 8 lines

Quoted 7 lines

In my view it should look for media devices first, query them and get all the device nodes referenced in the topology, and then fall back to the old method to discover any remaining device nodes for drivers that do not create a media device.

You need media device support anyway since you also want to be able to query the media device for a specific driver and find the device node for a specific entity.

Quoted 9 lines

Quoted 5 lines

I've been thinking about this (since I started with http://git.ideasonboard.org/media-enum.git),
but to be honest, I failed to see why I would want to query media devices.

Let's say we want to find a H264 decoder, I don't think the topology is be of much use, is it?

Not for codecs, but this should become a generic utility that you can also use to find e.g. v4l-subdev device nodes from a complex camera driver.

Ah, that makes sense.

Thanks for the quick review!

Quoted 58 lines

Regards,

Hans

Quoted 54 lines

In any case, I think this is part of a bigger discussion, would you consider merging v4l discovery for now?

Quoted 51 lines

Quoted 40 lines

utils/v4l2-get-device/v4l2-get-device.c new file +34 -0

+
+	vid = NULL;
+	do {
+		struct v4l2_capability cap;
+		char devnode[64];
+		int ret;
+		int fd;
+
+		vid = get_associated_device(md, vid, MEDIA_V4L_VIDEO,
+					    NULL, NONE);
+		if (!vid)
+			break;
+		snprintf(devnode, 64, "/dev/%s", vid);
+		fd = open(devnode, O_RDWR);
+		if (fd < 0)
+			continue;
+
+		memset(&cap, 0, sizeof cap);
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+		if (ret) {
+			close(fd);
+			continue;
+		}
+		close(fd);
+
+		if (strncmp(args.driver, (char *)cap.driver, sizeof(cap.driver)))
+			continue;
+		if (args.device_caps && (args.device_caps & cap.device_caps) != args.device_caps)
+			continue;
+		fprintf(stdout, "%s\n", devnode);
+	} while (vid);
+	free_media_devices(md);
+	return 0;
+}

v4l-utils.spec.in +0 -0

index 67bdca57ae92..ab15286b039b 100644

v4l-utils.spec.in gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || : · line 165

Quoted 7 lines

v4l-utils.spec.in +1 -0

@@ -159,6 +159,7 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 %{_bindir}/ivtv-ctl
 %{_bindir}/v4l2-ctl
 %{_bindir}/v4l2-sysfs-path
+%{_bindir}/v4l2-get-device
 %{_mandir}/man1/ir-keytable.1*
 %{_mandir}/man1/ir-ctl.1*
 

Regards,

Hans

Resurrecting this thread, since this functionality would be really useful :-)

Quoted 16 lines · Hans Verkuil

Quoted 15 lines · Ezequiel Garcia

Quoted 13 lines · Hans Verkuil

Quoted 8 lines · Ezequiel Garcia

Quoted 2 lines

This tool allows to find a device by driver name, this is useful for scripts to be written in a generic way.

Why not add support for this to v4l2-sysfs-path? And improve it at the same time (swradio devices do not show up when I run v4l2-sysfs-path, I also suspect v4l-touch devices aren't recognized. Ditto for media devices.

I can add the functionality to v4l2-sysfs-path, and we can document the rest in some TODO list, as I don't think we need to get everything solved right now :-)

Quoted 8 lines

Quoted 2 lines

I agree with that.

Great!

About adding it to v4l2-sysfs-path, is there any scenario where we'll want to use udev-based scanning instead of sysfs-based? Maybe we can rename the tool, and still install a v4l2-sysfs-path alias?

To be honest, I don't know. It appears that sysfs is the most generic approach and I have seen cases where udev isn't installed on an embedded system.

So I feel that sysfs is the best approach for now.

BTW, I've added support for swradio and v4l-touch devices to v4l2-sysfs-path, but I noticed that it didn't recognize media devices, I need to dig into it a bit to understand how to find those devices.

Regards,

Hans

Quoted 285 lines

Quoted 213 lines

Quoted 196 lines

Quoted 114 lines

Quoted 114 lines

Usage:

v4l2-get-device -d uvcvideo -c V4L2_CAP_VIDEO_CAPTURE /dev/video0
/dev/video2

Signed-off-by Ezequiel Garcia <[email protected]>

---
 configure.ac                            |   1 +
 utils/Makefile.am                       |   1 +
 utils/v4l2-get-device/.gitignore        |   1 +
 utils/v4l2-get-device/Makefile.am       |   4 +
 utils/v4l2-get-device/v4l2-get-device.c | 147 ++++++++++++++++++++++++
 v4l-utils.spec.in                       |   1 +
 6 files changed, 155 insertions(+)
 create mode 100644 utils/v4l2-get-device/.gitignore
 create mode 100644 utils/v4l2-get-device/Makefile.am
 create mode 100644 utils/v4l2-get-device/v4l2-get-device.c

configure.ac +1 -0

index 5cc34c248fbf..918cb59704b9 100644
@@ -31,6 +31,7 @@ AC_CONFIG_FILES([Makefile
 	utils/v4l2-compliance/Makefile
 	utils/v4l2-ctl/Makefile
 	utils/v4l2-dbg/Makefile
+	utils/v4l2-get-device/Makefile
 	utils/v4l2-sysfs-path/Makefile
 	utils/qv4l2/Makefile
 	utils/cec-ctl/Makefile

utils/Makefile.am +1 -0

index 2d5070288c13..2b2b27107d13 100644
@@ -9,6 +9,7 @@ SUBDIRS = \
 	v4l2-compliance \
 	v4l2-ctl \
 	v4l2-dbg \
+	v4l2-get-device \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \

utils/v4l2-get-device/.gitignore new file +1 -0

new file mode 100644
index 000000000000..b222144c9f4e
@@ -0,0 +1 @@
+v4l2-get-device

utils/v4l2-get-device/Makefile.am new file +4 -0

new file mode 100644
index 000000000000..2e5a6e0ba32f
@@ -0,0 +1,4 @@
+bin_PROGRAMS = v4l2-get-device
+v4l2_get_device_SOURCES = v4l2-get-device.c
+v4l2_get_device_LDADD = ../libmedia_dev/libmedia_dev.la
+v4l2_get_device_LDFLAGS = $(ARGP_LIBS)

utils/v4l2-get-device/v4l2-get-device.c new file +48 -0

new file mode 100644
index 000000000000..f9cc323b7057
@@ -0,0 +1,147 @@
+/*
+ * Copyright © 2018 Collabora, Ltd.
+ *
+ * Based on v4l2-sysfs-path by Mauro Carvalho Chehab:
+ *
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <argp.h>
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/unistd.h>
+
+#include <linux/videodev2.h>
+
+#include "../libmedia_dev/get_media_devices.h"
+
+const char *argp_program_version = "v4l2-get-device " V4L_UTILS_VERSION;
+const char *argp_program_bug_address = "Ezequiel Garcia <[email protected]>";
+
+struct args {
+	const char *driver;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 54

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+	unsigned int device_caps;
+};
+
+static const struct argp_option options[] = {
+	{"driver", 'd', "DRIVER", 0, "device driver name", 0},
+	{"v4l2-device-caps", 'c', "CAPS", 0, "v4l2 device capabilities", 0},

I'd like a bus-info option as well, if possible.

Guess that works.

Quoted 15 lines

Quoted 15 lines

utils/v4l2-get-device/v4l2-get-device.c new file +15 -0

+	{ 0 }
+};
+
+static unsigned int parse_capabilities(const char *arg)
+{
+	char *s, *str = strdup(arg);
+	unsigned int caps = 0;
+
+	s = strtok (str,",");
+	while (s != NULL) {
+		if (!strcmp(s, "V4L2_CAP_VIDEO_CAPTURE"))
+			caps |= V4L2_CAP_VIDEO_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OUTPUT"))
+			caps |= V4L2_CAP_VIDEO_OUTPUT;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OVERLAY"))

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 74

Quoted 5 lines

utils/v4l2-get-device/v4l2-get-device.c new file +5 -0

+			caps |= V4L2_CAP_VIDEO_OVERLAY;
+		else if (!strcmp(s, "V4L2_CAP_VBI_CAPTURE"))
+			caps |= V4L2_CAP_VBI_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VBI_OUTPUT"))
+			caps |= V4L2_CAP_VBI_OUTPUT;

Let's support all CAPS here. I'd also drop the V4L2_CAP_ prefix (or make it optional) and make the strcmp case-insensitive to ease typing.

OK.

Quoted 33 lines

Quoted 33 lines

utils/v4l2-get-device/v4l2-get-device.c new file +33 -0

+		s = strtok (NULL, ",");
+	}
+	free(str);
+	return caps;
+}
+
+static error_t parse_opt(int k, char *arg, struct argp_state *state)
+{
+	struct args *args = state->input;
+
+	switch (k) {
+	case 'd':
+		args->driver = arg;
+		break;
+	case 'c':
+		args->device_caps = parse_capabilities(arg);
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static struct argp argp = {
+	.options = options,
+	.parser = parse_opt,
+};
+
+int main(int argc, char *argv[])
+{
+	const char *vid;
+	struct args args;
+	void *md;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 113

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+
+	args.driver = NULL;
+	args.device_caps = 0;
+	argp_parse(&argp, argc, argv, 0, 0, &args);
+
+	md = discover_media_devices();

I never really liked this. My main problem is that it doesn't know about media devices.

Quoted 6 lines

Sorry, not sure what you don't really like?

The discover_media_devices() is maybe not the best API, but it's what v4l2-sysfs-path uses, and it seemed to fit what we need as a first step (to find v4l2 devices).

Perhaps we can use this for now and pospone improving the discovery library?

Yes, that can be postponed (I should have been clear about that, sorry).

Quoted 8 lines

Quoted 7 lines

In my view it should look for media devices first, query them and get all the device nodes referenced in the topology, and then fall back to the old method to discover any remaining device nodes for drivers that do not create a media device.

You need media device support anyway since you also want to be able to query the media device for a specific driver and find the device node for a specific entity.

Quoted 9 lines

Quoted 5 lines

I've been thinking about this (since I started with http://git.ideasonboard.org/media-enum.git),
but to be honest, I failed to see why I would want to query media devices.

Let's say we want to find a H264 decoder, I don't think the topology is be of much use, is it?

Not for codecs, but this should become a generic utility that you can also use to find e.g. v4l-subdev device nodes from a complex camera driver.

Ah, that makes sense.

Thanks for the quick review!

Quoted 58 lines

Regards,

Hans

Quoted 54 lines

In any case, I think this is part of a bigger discussion, would you consider merging v4l discovery for now?

Quoted 51 lines

Quoted 40 lines

utils/v4l2-get-device/v4l2-get-device.c new file +34 -0

+
+	vid = NULL;
+	do {
+		struct v4l2_capability cap;
+		char devnode[64];
+		int ret;
+		int fd;
+
+		vid = get_associated_device(md, vid, MEDIA_V4L_VIDEO,
+					    NULL, NONE);
+		if (!vid)
+			break;
+		snprintf(devnode, 64, "/dev/%s", vid);
+		fd = open(devnode, O_RDWR);
+		if (fd < 0)
+			continue;
+
+		memset(&cap, 0, sizeof cap);
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+		if (ret) {
+			close(fd);
+			continue;
+		}
+		close(fd);
+
+		if (strncmp(args.driver, (char *)cap.driver, sizeof(cap.driver)))
+			continue;
+		if (args.device_caps && (args.device_caps & cap.device_caps) != args.device_caps)
+			continue;
+		fprintf(stdout, "%s\n", devnode);
+	} while (vid);
+	free_media_devices(md);
+	return 0;
+}

v4l-utils.spec.in +0 -0

index 67bdca57ae92..ab15286b039b 100644

v4l-utils.spec.in gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || : · line 165

Quoted 7 lines

v4l-utils.spec.in +1 -0

@@ -159,6 +159,7 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 %{_bindir}/ivtv-ctl
 %{_bindir}/v4l2-ctl
 %{_bindir}/v4l2-sysfs-path
+%{_bindir}/v4l2-get-device
 %{_mandir}/man1/ir-keytable.1*
 %{_mandir}/man1/ir-ctl.1*
 

Regards,

Hans

Resurrecting this thread, since this functionality would be really useful :-)

Quoted 20 lines · Ezequiel Garcia

Quoted 11 lines · Hans Verkuil

Quoted 10 lines · Ezequiel Garcia

Quoted 8 lines · Hans Verkuil

Quoted 2 lines · Ezequiel Garcia

This tool allows to find a device by driver name, this is useful for scripts to be written in a generic way.

Why not add support for this to v4l2-sysfs-path? And improve it at the same time (swradio devices do not show up when I run v4l2-sysfs-path, I also suspect v4l-touch devices aren't recognized. Ditto for media devices.

Quoted 5 lines

Quoted 3 lines

I can add the functionality to v4l2-sysfs-path, and we can document the rest in some TODO list, as I don't think we need to get everything solved right now :-)

I agree with that.

Great!

Quoted 3 lines

About adding it to v4l2-sysfs-path, is there any scenario where we'll want to use udev-based scanning instead of sysfs-based? Maybe we can rename the tool, and still install a v4l2-sysfs-path alias?

To be honest, I don't know. It appears that sysfs is the most generic approach and I have seen cases where udev isn't installed on an embedded system.

So I feel that sysfs is the best approach for now.

BTW, I've added support for swradio and v4l-touch devices to v4l2-sysfs-path, but I noticed that it didn't recognize media devices, I need to dig into it a bit to understand how to find those devices.

Quoted 207 lines

Quoted 207 lines

Quoted 195 lines

Quoted 114 lines

Quoted 114 lines

Usage:

v4l2-get-device -d uvcvideo -c V4L2_CAP_VIDEO_CAPTURE /dev/video0
/dev/video2

Signed-off-by Ezequiel Garcia <[email protected]>

---
 configure.ac                            |   1 +
 utils/Makefile.am                       |   1 +
 utils/v4l2-get-device/.gitignore        |   1 +
 utils/v4l2-get-device/Makefile.am       |   4 +
 utils/v4l2-get-device/v4l2-get-device.c | 147 ++++++++++++++++++++++++
 v4l-utils.spec.in                       |   1 +
 6 files changed, 155 insertions(+)
 create mode 100644 utils/v4l2-get-device/.gitignore
 create mode 100644 utils/v4l2-get-device/Makefile.am
 create mode 100644 utils/v4l2-get-device/v4l2-get-device.c

configure.ac +1 -0

index 5cc34c248fbf..918cb59704b9 100644
@@ -31,6 +31,7 @@ AC_CONFIG_FILES([Makefile
 	utils/v4l2-compliance/Makefile
 	utils/v4l2-ctl/Makefile
 	utils/v4l2-dbg/Makefile
+	utils/v4l2-get-device/Makefile
 	utils/v4l2-sysfs-path/Makefile
 	utils/qv4l2/Makefile
 	utils/cec-ctl/Makefile

utils/Makefile.am +1 -0

index 2d5070288c13..2b2b27107d13 100644
@@ -9,6 +9,7 @@ SUBDIRS = \
 	v4l2-compliance \
 	v4l2-ctl \
 	v4l2-dbg \
+	v4l2-get-device \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \

utils/v4l2-get-device/.gitignore new file +1 -0

new file mode 100644
index 000000000000..b222144c9f4e
@@ -0,0 +1 @@
+v4l2-get-device

utils/v4l2-get-device/Makefile.am new file +4 -0

new file mode 100644
index 000000000000..2e5a6e0ba32f
@@ -0,0 +1,4 @@
+bin_PROGRAMS = v4l2-get-device
+v4l2_get_device_SOURCES = v4l2-get-device.c
+v4l2_get_device_LDADD = ../libmedia_dev/libmedia_dev.la
+v4l2_get_device_LDFLAGS = $(ARGP_LIBS)

utils/v4l2-get-device/v4l2-get-device.c new file +48 -0

new file mode 100644
index 000000000000..f9cc323b7057
@@ -0,0 +1,147 @@
+/*
+ * Copyright © 2018 Collabora, Ltd.
+ *
+ * Based on v4l2-sysfs-path by Mauro Carvalho Chehab:
+ *
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of Red Hat
+ * not be used in advertising or publicity pertaining to distribution
+ * of the software without specific, written prior permission.  Red
+ * Hat makes no representations about the suitability of this software
+ * for any purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <argp.h>
+#include <config.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/unistd.h>
+
+#include <linux/videodev2.h>
+
+#include "../libmedia_dev/get_media_devices.h"
+
+const char *argp_program_version = "v4l2-get-device " V4L_UTILS_VERSION;
+const char *argp_program_bug_address = "Ezequiel Garcia <[email protected]>";
+
+struct args {
+	const char *driver;

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 54

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+	unsigned int device_caps;
+};
+
+static const struct argp_option options[] = {
+	{"driver", 'd', "DRIVER", 0, "device driver name", 0},
+	{"v4l2-device-caps", 'c', "CAPS", 0, "v4l2 device capabilities", 0},

I'd like a bus-info option as well, if possible.

Guess that works.

Quoted 15 lines

Quoted 15 lines

utils/v4l2-get-device/v4l2-get-device.c new file +15 -0

+	{ 0 }
+};
+
+static unsigned int parse_capabilities(const char *arg)
+{
+	char *s, *str = strdup(arg);
+	unsigned int caps = 0;
+
+	s = strtok (str,",");
+	while (s != NULL) {
+		if (!strcmp(s, "V4L2_CAP_VIDEO_CAPTURE"))
+			caps |= V4L2_CAP_VIDEO_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OUTPUT"))
+			caps |= V4L2_CAP_VIDEO_OUTPUT;
+		else if (!strcmp(s, "V4L2_CAP_VIDEO_OVERLAY"))

Quoted 9 lines

utils/v4l2-get-device/v4l2-get-device.c line 74

Quoted 5 lines

utils/v4l2-get-device/v4l2-get-device.c new file +5 -0

+			caps |= V4L2_CAP_VIDEO_OVERLAY;
+		else if (!strcmp(s, "V4L2_CAP_VBI_CAPTURE"))
+			caps |= V4L2_CAP_VBI_CAPTURE;
+		else if (!strcmp(s, "V4L2_CAP_VBI_OUTPUT"))
+			caps |= V4L2_CAP_VBI_OUTPUT;

Let's support all CAPS here. I'd also drop the V4L2_CAP_ prefix (or make it optional) and make the strcmp case-insensitive to ease typing.

OK.

Quoted 33 lines

Quoted 33 lines

utils/v4l2-get-device/v4l2-get-device.c new file +33 -0

+		s = strtok (NULL, ",");
+	}
+	free(str);
+	return caps;
+}
+
+static error_t parse_opt(int k, char *arg, struct argp_state *state)
+{
+	struct args *args = state->input;
+
+	switch (k) {
+	case 'd':
+		args->driver = arg;
+		break;
+	case 'c':
+		args->device_caps = parse_capabilities(arg);
+		break;
+	default:
+		return ARGP_ERR_UNKNOWN;
+	}
+	return 0;
+}
+
+static struct argp argp = {
+	.options = options,
+	.parser = parse_opt,
+};
+
+int main(int argc, char *argv[])
+{
+	const char *vid;
+	struct args args;
+	void *md;

Quoted 8 lines

utils/v4l2-get-device/v4l2-get-device.c line 113

Quoted 6 lines

utils/v4l2-get-device/v4l2-get-device.c new file +6 -0

+
+	args.driver = NULL;
+	args.device_caps = 0;
+	argp_parse(&argp, argc, argv, 0, 0, &args);
+
+	md = discover_media_devices();

I never really liked this. My main problem is that it doesn't know about media devices.

Quoted 6 lines

Sorry, not sure what you don't really like?

The discover_media_devices() is maybe not the best API, but it's what v4l2-sysfs-path uses, and it seemed to fit what we need as a first step (to find v4l2 devices).

Perhaps we can use this for now and pospone improving the discovery library?

Yes, that can be postponed (I should have been clear about that, sorry).

Quoted 3 lines

Quoted 3 lines

In my view it should look for media devices first, query them and get all the device nodes referenced in the topology, and then fall back to the old method to discover any remaining device nodes for drivers that do not create a media device.

Quoted 64 lines

Quoted 11 lines

Quoted 8 lines

Quoted 2 lines

You need media device support anyway since you also want to be able to query the media device for a specific driver and find the device node for a specific entity.

I've been thinking about this (since I started with http://git.ideasonboard.org/media-enum.git),
but to be honest, I failed to see why I would want to query media devices.

Let's say we want to find a H264 decoder, I don't think the topology is be of much use, is it?

Not for codecs, but this should become a generic utility that you can also use to find e.g. v4l-subdev device nodes from a complex camera driver.

Ah, that makes sense.

Thanks for the quick review!

Quoted 48 lines

Quoted 48 lines

In any case, I think this is part of a bigger discussion, would you consider merging v4l discovery for now?

Quoted 45 lines

Quoted 45 lines

utils/v4l2-get-device/v4l2-get-device.c new file +34 -0

+
+	vid = NULL;
+	do {
+		struct v4l2_capability cap;
+		char devnode[64];
+		int ret;
+		int fd;
+
+		vid = get_associated_device(md, vid, MEDIA_V4L_VIDEO,
+					    NULL, NONE);
+		if (!vid)
+			break;
+		snprintf(devnode, 64, "/dev/%s", vid);
+		fd = open(devnode, O_RDWR);
+		if (fd < 0)
+			continue;
+
+		memset(&cap, 0, sizeof cap);
+		ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
+		if (ret) {
+			close(fd);
+			continue;
+		}
+		close(fd);
+
+		if (strncmp(args.driver, (char *)cap.driver, sizeof(cap.driver)))
+			continue;
+		if (args.device_caps && (args.device_caps & cap.device_caps) != args.device_caps)
+			continue;
+		fprintf(stdout, "%s\n", devnode);
+	} while (vid);
+	free_media_devices(md);
+	return 0;
+}

v4l-utils.spec.in +1 -0

index 67bdca57ae92..ab15286b039b 100644
@@ -159,6 +159,7 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 %{_bindir}/ivtv-ctl
 %{_bindir}/v4l2-ctl
 %{_bindir}/v4l2-sysfs-path
+%{_bindir}/v4l2-get-device
 %{_mandir}/man1/ir-keytable.1*
 %{_mandir}/man1/ir-ctl.1*