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Commit eac8ea53 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
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V4L/DVB (13549): v4l: Add video_device_node_name function 



Many drivers access the device number (video_device::v4l2_devnode::num)
in order to print the video device node name. Add and use a helper
function to retrieve the video_device node name.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent a3a9e287

Documentation/video4linux/v4l2-framework.txt

+14 −2
Original line number Diff line number Diff line
@@ -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

-----------------------------

drivers/media/video/v4l2-dev.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

include/media/v4l2-dev.h

+5 −0
Original line number Diff line number Diff line
@@ -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);