diff mbox series

[PATCHv3,4/4] dvbdev: add /sys media_dev attr for DVB devices

Message ID 20210202144926.620104-5-hverkuil-cisco@xs4all.nl (mailing list archive)
State TODO, archived
Delegated to: Hans Verkuil
Headers
Series Add /sys media_dev attr for V4L/DVB devices |

Commit Message

Hans Verkuil Feb. 2, 2021, 2:49 p.m. UTC 
  For each DVB device node create a media_dev attribute in /sys
which contains the media device major and minor number.

It is not created if the CONFIG_MEDIA_CONTROLLER_DVB is not
defined or if there is no associated media device.

This makes it possible for applications like v4l2-compliance
to find the associated media controller of a DVB device.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/dvb-core/dvbdev.c | 45 +++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
diff mbox series

Patch

diff --git a/drivers/media/dvb-core/dvbdev.c b/drivers/media/dvb-core/dvbdev.c
index 5ff7bedee247..db8bddcc5780 100644
--- a/drivers/media/dvb-core/dvbdev.c
+++ b/drivers/media/dvb-core/dvbdev.c
@@ -452,6 +452,48 @@  static int dvb_register_media_device(struct dvb_device *dvbdev,
 	return 0;
 }
 
+#if defined(CONFIG_MEDIA_CONTROLLER_DVB)
+static ssize_t media_dev_show(struct device *cd,
+			      struct device_attribute *attr, char *buf)
+{
+	struct dvb_device *dvbdev = dev_get_drvdata(cd);
+	dev_t devt = media_device_devt(dvbdev->adapter->mdev);
+
+	buf[0] = '\0';
+	if (!devt)
+		return 0;
+	return sprintf(buf, "%u:%u\n", MAJOR(devt), MINOR(devt));
+}
+static DEVICE_ATTR_RO(media_dev);
+
+static umode_t dvb_device_attr_is_visible(struct kobject *kobj,
+					  struct attribute *attr, int n)
+{
+	struct dvb_device *dvbdev = dev_get_drvdata(kobj_to_dev(kobj));
+
+	if (attr == &dev_attr_media_dev.attr) {
+		if (!dvbdev->adapter->mdev)
+			return 0;
+	}
+	return attr->mode;
+}
+
+static struct attribute *dvb_device_attrs[] = {
+	&dev_attr_media_dev.attr,
+	NULL,
+};
+
+static const struct attribute_group dvb_device_group = {
+	.is_visible = dvb_device_attr_is_visible,
+	.attrs = dvb_device_attrs,
+};
+
+static const struct attribute_group *dvb_device_groups[] = {
+	&dvb_device_group,
+	NULL
+};
+#endif
+
 int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev,
 			const struct dvb_device *template, void *priv,
 			enum dvb_device_type type, int demux_sink_pads)
@@ -1056,6 +1098,9 @@  static int __init init_dvbdev(void)
 	}
 	dvb_class->dev_uevent = dvb_uevent;
 	dvb_class->devnode = dvb_devnode;
+#if defined(CONFIG_MEDIA_CONTROLLER_DVB)
+	dvb_class->dev_groups = dvb_device_groups;
+#endif
 	return 0;
 
 error: