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-rw-r--r--Documentation/video4linux/v4l2-framework.txt16
-rw-r--r--drivers/media/video/v4l2-dev.c4
-rw-r--r--include/media/v4l2-dev.h5
3 files changed, 21 insertions, 4 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index b806eda..74d677c 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -561,6 +561,8 @@ video_device helper functions
There are a few useful helper functions:
+- file/video_device private data
+
You can set/get driver private data in the video_device struct using:
void *video_get_drvdata(struct video_device *vdev);
@@ -575,8 +577,7 @@ struct video_device *video_devdata(struct file *file);
returns the video_device belonging to the file struct.
-The final helper function combines video_get_drvdata with
-video_devdata:
+The video_drvdata function combines video_get_drvdata with video_devdata:
void *video_drvdata(struct file *file);
@@ -584,6 +585,17 @@ You can go from a video_device struct to the v4l2_device struct using:
struct v4l2_device *v4l2_dev = vdev->v4l2_dev;
+- Device node name
+
+The video_device node kernel name can be retrieved using
+
+const char *video_device_node_name(struct video_device *vdev);
+
+The name is used as a hint by userspace tools such as udev. The function
+should be used where possible instead of accessing the video_device::num and
+video_device::minor fields.
+
+
video buffer helper functions
-----------------------------
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
index 500cbe9..aa3e0f9 100644
--- a/drivers/media/video/v4l2-dev.c
+++ b/drivers/media/video/v4l2-dev.c
@@ -551,8 +551,8 @@ static int __video_register_device(struct video_device *vdev, int type, int nr,
vdev->dev.release = v4l2_device_release;
if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
- printk(KERN_WARNING "%s: requested %s%d, got %s%d\n",
- __func__, name_base, nr, name_base, vdev->num);
+ printk(KERN_WARNING "%s: requested %s%d, got %s\n", __func__,
+ name_base, nr, video_device_node_name(vdev));
/* Part 5: Activate this minor. The char device can now be used. */
mutex_lock(&videodev_lock);
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index 73c9867..9135f57 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -141,6 +141,11 @@ static inline void *video_drvdata(struct file *file)
return video_get_drvdata(video_devdata(file));
}
+static inline const char *video_device_node_name(struct video_device *vdev)
+{
+ return dev_name(&vdev->dev);
+}
+
static inline int video_is_unregistered(struct video_device *vdev)
{
return test_bit(V4L2_FL_UNREGISTERED, &vdev->flags);
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