v4l2-dev.h

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/*
 *
 *  V 4 L 2   D R I V E R   H E L P E R   A P I
 *
 * Moved from videodev2.h
 *
 *  Some commonly needed functions for drivers (v4l2-common.o module)
 */
#ifndef _V4L2_DEV_H
#define _V4L2_DEV_H

#include <linux/poll.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/mutex.h>
#include <linux/videodev2.h>

#include <media/media-entity.h>

#define VIDEO_MAJOR 81

#define VFL_TYPE_GRABBER    0
#define VFL_TYPE_VBI        1
#define VFL_TYPE_RADIO      2
#define VFL_TYPE_SUBDEV     3
#define VFL_TYPE_MAX        4

/* Is this a receiver, transmitter or mem-to-mem? */
/* Ignored for VFL_TYPE_SUBDEV. */
#define VFL_DIR_RX      0
#define VFL_DIR_TX      1
#define VFL_DIR_M2M     2

struct v4l2_ioctl_callbacks;
struct video_device;
struct v4l2_device;
struct v4l2_ctrl_handler;

/* Flag to mark the video_device struct as registered.
   Drivers can clear this flag if they want to block all future
   device access. It is cleared by video_unregister_device. */
#define V4L2_FL_REGISTERED  (0)
/* file->private_data points to struct v4l2_fh */
#define V4L2_FL_USES_V4L2_FH    (1)
/* Use the prio field of v4l2_fh for core priority checking */
#define V4L2_FL_USE_FH_PRIO (2)

/* Priority helper functions */

struct v4l2_prio_state {
    atomic_t prios[4];
};

void v4l2_prio_init(struct v4l2_prio_state *global);
int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
             enum v4l2_priority new);
void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);


struct v4l2_file_operations {
    struct module *owner;
    ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
    ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
    unsigned int (*poll) (struct file *, struct poll_table_struct *);
    long (*ioctl) (struct file *, unsigned int, unsigned long);
    long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
#ifdef CONFIG_COMPAT
    long (*compat_ioctl32) (struct file *, unsigned int, unsigned long);
#endif
    unsigned long (*get_unmapped_area) (struct file *, unsigned long,
                unsigned long, unsigned long, unsigned long);
    int (*mmap) (struct file *, struct vm_area_struct *);
    int (*open) (struct file *);
    int (*release) (struct file *);
};

/*
 * Newer version of video_device, handled by videodev2.c
 *  This version moves redundant code from video device code to
 *  the common handler
 */

struct video_device
{
#if defined(CONFIG_MEDIA_CONTROLLER)
    struct media_entity entity;
#endif
    /* device ops */
    const struct v4l2_file_operations *fops;

    /* sysfs */
    struct device dev;      /* v4l device */
    struct cdev *cdev;      /* character device */

    /* Set either parent or v4l2_dev if your driver uses v4l2_device */
    struct device *parent;      /* device parent */
    struct v4l2_device *v4l2_dev;   /* v4l2_device parent */

    /* Control handler associated with this device node. May be NULL. */
    struct v4l2_ctrl_handler *ctrl_handler;

    /* vb2_queue associated with this device node. May be NULL. */
    struct vb2_queue *queue;

    /* Priority state. If NULL, then v4l2_dev->prio will be used. */
    struct v4l2_prio_state *prio;

    /* device info */
    char name[32];
    int vfl_type;   /* device type */
    int vfl_dir;    /* receiver, transmitter or m2m */
    /* 'minor' is set to -1 if the registration failed */
    int minor;
    u16 num;
    /* use bitops to set/clear/test flags */
    unsigned long flags;
    /* attribute to differentiate multiple indices on one physical device */
    int index;

    /* V4L2 file handles */
    spinlock_t      fh_lock; /* Lock for all v4l2_fhs */
    struct list_head    fh_list; /* List of struct v4l2_fh */

    int debug;          /* Activates debug level*/

    /* Video standard vars */
    v4l2_std_id tvnorms;        /* Supported tv norms */
    v4l2_std_id current_norm;   /* Current tvnorm */

    /* callbacks */
    void (*release)(struct video_device *vdev);

    /* ioctl callbacks */
    const struct v4l2_ioctl_ops *ioctl_ops;
    DECLARE_BITMAP(valid_ioctls, BASE_VIDIOC_PRIVATE);

    /* serialization lock */
    DECLARE_BITMAP(disable_locking, BASE_VIDIOC_PRIVATE);
    struct mutex *lock;
};

#define media_entity_to_video_device(__e) \
    container_of(__e, struct video_device, entity)
/* dev to video-device */
#define to_video_device(cd) container_of(cd, struct video_device, dev)

int __must_check __video_register_device(struct video_device *vdev, int type,
        int nr, int warn_if_nr_in_use, struct module *owner);

/* Register video devices. Note that if video_register_device fails,
   the release() callback of the video_device structure is *not* called, so
   the caller is responsible for freeing any data. Usually that means that
   you call video_device_release() on failure. */
static inline int __must_check video_register_device(struct video_device *vdev,
        int type, int nr)
{
    return __video_register_device(vdev, type, nr, 1, vdev->fops->owner);
}

/* Same as video_register_device, but no warning is issued if the desired
   device node number was already in use. */
static inline int __must_check video_register_device_no_warn(
        struct video_device *vdev, int type, int nr)
{
    return __video_register_device(vdev, type, nr, 0, vdev->fops->owner);
}

/* Unregister video devices. Will do nothing if vdev == NULL or
   video_is_registered() returns false. */
void video_unregister_device(struct video_device *vdev);

/* helper functions to alloc/release struct video_device, the
   latter can also be used for video_device->release(). */
struct video_device * __must_check video_device_alloc(void);

/* this release function frees the vdev pointer */
void video_device_release(struct video_device *vdev);

/* this release function does nothing, use when the video_device is a
   static global struct. Note that having a static video_device is
   a dubious construction at best. */
void video_device_release_empty(struct video_device *vdev);

/* returns true if cmd is a known V4L2 ioctl */
bool v4l2_is_known_ioctl(unsigned int cmd);

/* mark that this command shouldn't use core locking */
static inline void v4l2_disable_ioctl_locking(struct video_device *vdev, unsigned int cmd)
{
    if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
        set_bit(_IOC_NR(cmd), vdev->disable_locking);
}

/* Mark that this command isn't implemented. This must be called before
   video_device_register. See also the comments in determine_valid_ioctls().
   This function allows drivers to provide just one v4l2_ioctl_ops struct, but
   disable ioctls based on the specific card that is actually found. */
static inline void v4l2_disable_ioctl(struct video_device *vdev, unsigned int cmd)
{
    if (_IOC_NR(cmd) < BASE_VIDIOC_PRIVATE)
        set_bit(_IOC_NR(cmd), vdev->valid_ioctls);
}

/* helper functions to access driver private data. */
static inline void *video_get_drvdata(struct video_device *vdev)
{
    return dev_get_drvdata(&vdev->dev);
}

static inline void video_set_drvdata(struct video_device *vdev, void *data)
{
    dev_set_drvdata(&vdev->dev, data);
}

struct video_device *video_devdata(struct file *file);

/* Combine video_get_drvdata and video_devdata as this is
   used very often. */
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_registered(struct video_device *vdev)
{
    return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
}

#endif /* _V4L2_DEV_H */