dd89601d47
The v4l core creates four different video devices (video, vbi, radio, vtx) and each has its own range of minor numbers. However, modern devices keep increasing the number of devices that they need so a maximum of 64 video devices will not be enough in the future. In addition this scheme makes it very hard to add new device types. This patch disconnects the kernel number allocation (e.g. video0, video1, etc.) from the actual minor number (just pick the first free minor). This allows for much more flexibility in the future. However, it does require the use of udev. For those who cannot use udev a new CONFIG option was created that changes the allocation scheme back to the old behavior. Thanks to Greg KH for suggesting this approach during the 2008 LPC. In addition, several bugs were fixed in the ivtv and cx18 drivers: these drivers try to allocate specific kernel numbers but that scheme contained a bug which caused what should have been e.g. video17 to appear as e.g. video2. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
111 lines
3 KiB
C
111 lines
3 KiB
C
/*
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*
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* V 4 L 2 D R I V E R H E L P E R A P I
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*
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* Moved from videodev2.h
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*
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* Some commonly needed functions for drivers (v4l2-common.o module)
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*/
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#ifndef _V4L2_DEV_H
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#define _V4L2_DEV_H
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#include <linux/poll.h>
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#include <linux/fs.h>
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#include <linux/device.h>
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#include <linux/cdev.h>
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#include <linux/mutex.h>
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#include <linux/videodev2.h>
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#define VIDEO_MAJOR 81
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#define VFL_TYPE_GRABBER 0
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#define VFL_TYPE_VBI 1
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#define VFL_TYPE_RADIO 2
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#define VFL_TYPE_VTX 3
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#define VFL_TYPE_MAX 4
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struct v4l2_ioctl_callbacks;
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/*
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* Newer version of video_device, handled by videodev2.c
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* This version moves redundant code from video device code to
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* the common handler
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*/
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struct video_device
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{
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/* device ops */
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const struct file_operations *fops;
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/* sysfs */
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struct device dev; /* v4l device */
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struct cdev cdev; /* character device */
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void (*cdev_release)(struct kobject *kobj);
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struct device *parent; /* device parent */
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/* device info */
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char name[32];
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int vfl_type;
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int minor;
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u16 num;
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/* attribute to differentiate multiple indices on one physical device */
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int index;
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int debug; /* Activates debug level*/
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/* Video standard vars */
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v4l2_std_id tvnorms; /* Supported tv norms */
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v4l2_std_id current_norm; /* Current tvnorm */
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/* callbacks */
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void (*release)(struct video_device *vfd);
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/* ioctl callbacks */
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const struct v4l2_ioctl_ops *ioctl_ops;
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};
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/* dev to video-device */
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#define to_video_device(cd) container_of(cd, struct video_device, dev)
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/* Register and unregister devices. Note that if video_register_device fails,
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the release() callback of the video_device structure is *not* called, so
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the caller is responsible for freeing any data. Usually that means that
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you call video_device_release() on failure. */
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int __must_check video_register_device(struct video_device *vfd, int type, int nr);
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int __must_check video_register_device_index(struct video_device *vfd,
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int type, int nr, int index);
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void video_unregister_device(struct video_device *vfd);
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/* helper functions to alloc/release struct video_device, the
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latter can also be used for video_device->release(). */
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struct video_device * __must_check video_device_alloc(void);
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/* this release function frees the vfd pointer */
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void video_device_release(struct video_device *vfd);
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/* this release function does nothing, use when the video_device is a
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static global struct. Note that having a static video_device is
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a dubious construction at best. */
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void video_device_release_empty(struct video_device *vfd);
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/* helper functions to access driver private data. */
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static inline void *video_get_drvdata(struct video_device *dev)
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{
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return dev_get_drvdata(&dev->dev);
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}
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static inline void video_set_drvdata(struct video_device *dev, void *data)
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{
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dev_set_drvdata(&dev->dev, data);
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}
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struct video_device *video_devdata(struct file *file);
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/* Combine video_get_drvdata and video_devdata as this is
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used very often. */
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static inline void *video_drvdata(struct file *file)
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{
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return video_get_drvdata(video_devdata(file));
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}
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#endif /* _V4L2_DEV_H */
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