Replace the video_is_unregistered function by a video_is_registered
function. The V4L2_FL_UNREGISTERED flag is replaced by a
V4L2_FL_REGISTERED flag.

This change makes the video_is_registered function return coherent
results when called on an initialize but not yet registered video_device
instance. The function can now be used instead of checking
video_device::minor.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

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: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Warn when the desired device node number is already in use, except when
the new video_register_device_no_warn function is called since in some
use-cases that warning is not relevant.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

video_register_device_index is never actually called, instead the
stream index number is always calculated automatically.

This patch removes this function and simplifies the internal get_index
function since that can now always just return the first free index.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Shared memory mappings on nommu machines require a get_unmapped_area
file operation that suggests an address for the mapping. This patch
adds a way for v4l2 drivers to provide this callback.

Signed-off-by: Daniel Glöckner <dg@emlix.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Since internal to v4l2 the ioctl prototype is the same regardless of it
being called through .ioctl or .unlocked_ioctl, we need to convert it all
to the long return type of unlocked_ioctl.

Thanks to Jean-Francois Moine for posting an initial patch for this and
thus bringing it to our attention.

Cc: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Introduce a struct v4l2_file_operations for v4l2 drivers.

Remove the unnecessary inode argument.

Move compat32 handling (and llseek) into the v4l2-dev core: this is now
handled in the v4l2 core and no longer in the drivers themselves.

Note that this changeset reverts an earlier patch that changed the return
type of__video_ioctl2 from int to long. This change will be reinstated
later in a much improved version.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Drivers that use v4l2_device can set that as parent pointer in the v4l2_dev
field instead of using the struct device parent field.

This allows v4l2-dev.c to check whether this driver is v4l2_device based,
and if so then it can offer additional services.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Instead of relying on the cdev release callback we should rely on the
release callback from the device struct. This requires that we use
get_device/put_device to do proper refcounting. In order to do this
safely v4l2-dev.c now sets up its own file_operations that call
out to the driver's ops.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

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>