Add documentation for v4l2-dev.h, and put it at v4l2-framework.rst,
where struct video_device is currently documented.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
---
Documentation/media/kapi/v4l2-framework.rst | 5 +
drivers/media/v4l2-core/v4l2-dev.c | 34 ---
include/media/v4l2-dev.h | 364 ++++++++++++++++++++++++----
3 files changed, 320 insertions(+), 83 deletions(-)
diff --git a/Documentation/media/kapi/v4l2-framework.rst b/Documentation/media/kapi/v4l2-framework.rst
index de341fc5b235..315388ef6593 100644
--- a/Documentation/media/kapi/v4l2-framework.rst
+++ b/Documentation/media/kapi/v4l2-framework.rst
@@ -699,3 +699,8 @@ methods.
It is expected that once the CCF becomes available on all relevant
architectures this API will be removed.
+
+video_device kAPI
+^^^^^^^^^^^^^^^^^
+
+.. kernel-doc:: include/media/v4l2-dev.h
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index 70b559d7ca80..e6da353b39bc 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -812,40 +812,6 @@ static int video_register_media_controller(struct video_device *vdev, int type)
return 0;
}
-/**
- * __video_register_device - register video4linux devices
- * @vdev: video device structure we want to register
- * @type: type of device to register
- * @nr: which device node number (0 == /dev/video0, 1 == /dev/video1, ...
- * -1 == first free)
- * @warn_if_nr_in_use: warn if the desired device node number
- * was already in use and another number was chosen instead.
- * @owner: module that owns the video device node
- *
- * The registration code assigns minor numbers and device node numbers
- * based on the requested type and registers the new device node with
- * the kernel.
- *
- * This function assumes that struct video_device was zeroed when it
- * was allocated and does not contain any stale date.
- *
- * An error is returned if no free minor or device node number could be
- * found, or if the registration of the device node failed.
- *
- * Zero is returned on success.
- *
- * Valid types are
- *
- * %VFL_TYPE_GRABBER - A frame grabber
- *
- * %VFL_TYPE_VBI - Vertical blank data (undecoded)
- *
- * %VFL_TYPE_RADIO - A radio card
- *
- * %VFL_TYPE_SUBDEV - A subdevice
- *
- * %VFL_TYPE_SDR - Software Defined Radio
- */
int __video_register_device(struct video_device *vdev, int type, int nr,
int warn_if_nr_in_use, struct module *owner)
{
diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h
index 25a3190308fb..5921c24565cf 100644
--- a/include/media/v4l2-dev.h
+++ b/include/media/v4l2-dev.h
@@ -47,19 +47,105 @@ struct v4l2_ctrl_handler;
/* Priority helper functions */
+/**
+ * struct v4l2_prio_state - stores the priority states
+ *
+ * @prios: array with elements to store the array priorities
+ *
+ *
+ * .. note::
+ * The size of @prios array matches the number of priority types defined
+ * by :ref:`enum v4l2_priority <v4l2-priority>`.
+ */
struct v4l2_prio_state {
atomic_t prios[4];
};
+/**
+ * v4l2_prio_init - initializes a struct v4l2_prio_state
+ *
+ * @global: pointer to &struct v4l2_prio_state
+ */
void v4l2_prio_init(struct v4l2_prio_state *global);
+
+/**
+ * v4l2_prio_change - changes the v4l2 file handler priority
+ *
+ * @global: pointer to the &struct v4l2_prio_state of the device node.
+ * @local: pointer to the desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>`
+ * @new: Priority type requested, as defined by :ref:`enum v4l2_priority <v4l2-priority>`.
+ *
+ * .. note::
+ * This function should be used only by the V4L2 core.
+ */
int v4l2_prio_change(struct v4l2_prio_state *global, enum v4l2_priority *local,
enum v4l2_priority new);
+
+/**
+ * v4l2_prio_open - Implements the priority logic for a file handler open
+ *
+ * @global: pointer to the &struct v4l2_prio_state of the device node.
+ * @local: pointer to the desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>`
+ *
+ * .. note::
+ * This function should be used only by the V4L2 core.
+ */
void v4l2_prio_open(struct v4l2_prio_state *global, enum v4l2_priority *local);
+
+/**
+ * v4l2_prio_close - Implements the priority logic for a file handler close
+ *
+ * @global: pointer to the &struct v4l2_prio_state of the device node.
+ * @local: priority to be released, as defined by :ref:`enum v4l2_priority <v4l2-priority>`
+ *
+ * .. note::
+ * This function should be used only by the V4L2 core.
+ */
void v4l2_prio_close(struct v4l2_prio_state *global, enum v4l2_priority local);
+
+/**
+ * v4l2_prio_max - Return the maximum priority, as stored at the @global array.
+ *
+ * @global: pointer to the &struct v4l2_prio_state of the device node.
+ *
+ * .. note::
+ * This function should be used only by the V4L2 core.
+ */
enum v4l2_priority v4l2_prio_max(struct v4l2_prio_state *global);
+
+/**
+ * v4l2_prio_close - Implements the priority logic for a file handler close
+ *
+ * @global: pointer to the &struct v4l2_prio_state of the device node.
+ * @local: desired priority, as defined by :ref:`enum v4l2_priority <v4l2-priority>` local
+ *
+ * .. note::
+ * This function should be used only by the V4L2 core.
+ */
int v4l2_prio_check(struct v4l2_prio_state *global, enum v4l2_priority local);
-
+/**
+ * struct v4l2_file_operations - fs operations used by a V4L2 device
+ *
+ * @owner: pointer to struct module
+ * @read: operations needed to implement the read() syscall
+ * @write: operations needed to implement the write() syscall
+ * @poll: operations needed to implement the poll() syscall
+ * @unlocked_ioctl: operations needed to implement the ioctl() syscall
+ * @compat_ioctl32: operations needed to implement the ioctl() syscall for
+ * the special case where the Kernel uses 64 bits instructions, but
+ * the userspace uses 32 bits.
+ * @get_unmapped_area: called by the mmap() syscall, used when %!CONFIG_MMU
+ * @mmap: operations needed to implement the mmap() syscall
+ * @open: operations needed to implement the open() syscall
+ * @release: operations needed to implement the release() syscall
+ *
+ * .. note::
+ *
+ * Those operations are used to implemente the fs struct file_operations
+ * at the V4L2 drivers. The V4L2 core overrides the fs ops with some
+ * extra logic needed by the subsystem.
+ */
struct v4l2_file_operations {
struct module *owner;
ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
@@ -82,6 +168,47 @@ struct v4l2_file_operations {
* the common handler
*/
+/**
+ * struct video_device - Structure used to create and manage the V4L2 device
+ * nodes.
+ *
+ * @entity: &struct media_entity
+ * @intf_devnode: pointer to &struct media_intf_devnode
+ * @pipe: &struct media_pipeline
+ * @fops: pointer to &struct v4l2_file_operations for the video device
+ * @device_caps: device capabilities as used in v4l2_capabilities
+ * @dev: &struct device for the video device
+ * @cdev: character device
+ * @v4l2_dev: pointer to &struct v4l2_device parent
+ * @dev_parent: pointer to &struct device parent
+ * @ctrl_handler: Control handler associated with this device node.
+ * May be NULL.
+ * @queue: &struct vb2_queue associated with this device node. May be NULL.
+ * @prio: pointer to &struct v4l2_prio_state with device's Priority state.
+ * If NULL, then v4l2_dev->prio will be used.
+ * @name: video device name
+ * @vfl_type: V4L device type
+ * @vfl_dir: V4L receiver, transmitter or m2m
+ * @minor: device node 'minor'. It is set to -1 if the registration failed
+ * @num: number of the video device node
+ * @flags: video device flags. Use bitops to set/clear/test flags
+ * @index: attribute to differentiate multiple indices on one physical device
+ * @fh_lock: Lock for all v4l2_fhs
+ * @fh_list: List of &struct v4l2_fh
+ * @dev_debug: Internal device debug flags, not for use by drivers
+ * @tvnorms: Supported tv norms
+ *
+ * @release: video device release() callback
+ * @ioctl_ops: pointer to &struct v4l2_ioctl_ops with ioctl callbacks
+ *
+ * @valid_ioctls: bitmap with the valid ioctls for this device
+ * @disable_locking: bitmap with the ioctls that don't require locking
+ * @lock: pointer to &struct mutex serialization lock
+ *
+ * .. note::
+ * Only set @dev_parent if that can't be deduced from @v4l2_dev.
+ */
+
struct video_device
{
#if defined(CONFIG_MEDIA_CONTROLLER)
@@ -89,59 +216,45 @@ struct video_device
struct media_intf_devnode *intf_devnode;
struct media_pipeline pipe;
#endif
- /* device ops */
const struct v4l2_file_operations *fops;
- /* device capabilities as used in v4l2_capabilities */
u32 device_caps;
/* sysfs */
- struct device dev; /* v4l device */
- struct cdev *cdev; /* character device */
+ struct device dev;
+ struct cdev *cdev;
- struct v4l2_device *v4l2_dev; /* v4l2_device parent */
- /* Only set parent if that can't be deduced from v4l2_dev */
- struct device *dev_parent; /* device parent */
+ struct v4l2_device *v4l2_dev;
+ struct device *dev_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 vfl_type;
+ int vfl_dir;
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 */
+ spinlock_t fh_lock;
+ struct list_head fh_list;
- /* Internal device debug flags, not for use by drivers */
int dev_debug;
- /* Video standard vars */
- v4l2_std_id tvnorms; /* Supported tv norms */
+ v4l2_std_id tvnorms;
/* 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;
};
@@ -151,88 +264,241 @@ struct video_device
/* dev to video-device */
#define to_video_device(cd) container_of(cd, struct video_device, dev)
+/**
+ * __video_register_device - register video4linux devices
+ *
+ * @vdev: struct video_device to register
+ * @type: type of device to register
+ * @nr: which device node number is desired:
+ * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
+ * @warn_if_nr_in_use: warn if the desired device node number
+ * was already in use and another number was chosen instead.
+ * @owner: module that owns the video device node
+ *
+ * The registration code assigns minor numbers and device node numbers
+ * based on the requested type and registers the new device node with
+ * the kernel.
+ *
+ * This function assumes that struct video_device was zeroed when it
+ * was allocated and does not contain any stale date.
+ *
+ * An error is returned if no free minor or device node number could be
+ * found, or if the registration of the device node failed.
+ *
+ * Returns 0 on success.
+ *
+ * Valid values for @type are:
+ *
+ * - %VFL_TYPE_GRABBER - A frame grabber
+ * - %VFL_TYPE_VBI - Vertical blank data (undecoded)
+ * - %VFL_TYPE_RADIO - A radio card
+ * - %VFL_TYPE_SUBDEV - A subdevice
+ * - %VFL_TYPE_SDR - Software Defined Radio
+ *
+ * .. note::
+ *
+ * This function is meant to be used only inside the V4L2 core.
+ * Drivers should use video_register_device() or
+ * video_register_device_no_warn().
+ */
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. */
+/**
+ * video_register_device - register video4linux devices
+ *
+ * @vdev: struct video_device to register
+ * @type: type of device to register
+ * @nr: which device node number is desired:
+ * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
+ *
+ * Internally, it calls __video_register_device(). Please see its
+ * documentation for more details.
+ *
+ * .. note::
+ * if video_register_device fails, the release() callback of
+ * &struct video_device structure is *not* called, so the caller
+ * is responsible for freeing any data. Usually that means that
+ * you video_device_release() should be called 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. */
+/**
+ * video_register_device_no_warn - register video4linux devices
+ *
+ * @vdev: struct video_device to register
+ * @type: type of device to register
+ * @nr: which device node number is desired:
+ * (0 == /dev/video0, 1 == /dev/video1, ..., -1 == first free)
+ *
+ * This function is identical to video_register_device() except that no
+ * warning is issued if the desired device node number was already in use.
+ *
+ * Internally, it calls __video_register_device(). Please see its
+ * documentation for more details.
+ *
+ * .. note::
+ * if video_register_device fails, the release() callback of
+ * &struct video_device structure is *not* called, so the caller
+ * is responsible for freeing any data. Usually that means that
+ * you video_device_release() should be called on failure.
+ */
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. */
+/**
+ * video_unregister_device - Unregister video devices.
+ *
+ * @vdev: &struct video_device to register
+ *
+ * Does nothing if vdev == NULL or if 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(). */
+/**
+ * video_device_alloc - helper function to alloc &struct video_device
+ *
+ * Returns NULL if %-ENOMEM or a &struct video_device on success.
+ */
struct video_device * __must_check video_device_alloc(void);
-/* this release function frees the vdev pointer */
+/**
+ * video_device_release - helper function to release &struct video_device
+ *
+ * @vdev: pointer to &struct video_device
+ *
+ * Can also be used for video_device->release().
+ */
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. */
+/**
+ * video_device_release_empty - helper function to implement the
+ * video_device->release() callback.
+ *
+ * @vdev: pointer to &struct video_device
+ *
+ * This release function does nothing.
+ *
+ * It should be used when the video_device is a static global struct.
+ *
+ * .. note::
+ * 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 */
+/**
+ * v4l2_is_known_ioctl - Checks if a given cmd is a known V4L ioctl
+ *
+ * @cmd: ioctl command
+ *
+ * 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)
+/** v4l2_disable_ioctl_locking - mark that a given command
+ * shouldn't use core locking
+ *
+ * @vdev: pointer to &struct video_device
+ * @cmd: ioctl command
+ */
+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)
+/**
+ * v4l2_disable_ioctl- mark that a given command isn't implemented.
+ * shouldn't use core locking
+ *
+ * @vdev: pointer to &struct video_device
+ * @cmd: ioctl command
+ *
+ * This function allows drivers to provide just one v4l2_ioctl_ops struct, but
+ * disable ioctls based on the specific card that is actually found.
+ *
+ * .. note::
+ *
+ * This must be called before video_register_device.
+ * See also the comments for determine_valid_ioctls().
+ */
+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. */
+/**
+ * video_get_drvdata - gets private data from &struct video_device.
+ *
+ * @vdev: pointer to &struct video_device
+ *
+ * returns a pointer to the private data
+ */
static inline void *video_get_drvdata(struct video_device *vdev)
{
return dev_get_drvdata(&vdev->dev);
}
+/**
+ * video_set_drvdata - sets private data from &struct video_device.
+ *
+ * @vdev: pointer to &struct video_device
+ * @data: private data pointer
+ */
static inline void video_set_drvdata(struct video_device *vdev, void *data)
{
dev_set_drvdata(&vdev->dev, data);
}
+/**
+ * video_devdata - gets &struct video_device from struct file.
+ *
+ * @file: pointer to struct file
+ */
struct video_device *video_devdata(struct file *file);
-/* Combine video_get_drvdata and video_devdata as this is
- used very often. */
+/**
+ * video_drvdata - gets private data from &struct video_device using the
+ * struct file.
+ *
+ * @file: pointer to struct file
+ *
+ * This is function combines both 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));
}
+/**
+ * video_device_node_name - returns the video device name
+ *
+ * @vdev: pointer to &struct video_device
+ *
+ * Returns the device name string
+ */
static inline const char *video_device_node_name(struct video_device *vdev)
{
return dev_name(&vdev->dev);
}
+/**
+ * video_is_registered - returns true if the &struct video_device is registered.
+ *
+ *
+ * @vdev: pointer to &struct video_device
+ */
static inline int video_is_registered(struct video_device *vdev)
{
return test_bit(V4L2_FL_REGISTERED, &vdev->flags);
--
2.7.4
--
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