The BKL replacement mutex had some serious performance side-effects on
V4L drivers. It is replaced by a better heuristic that works around the
worst of the side-effects.

Read the v4l2-dev.c comments for the whole sorry story. This is a
temporary measure only until we can convert all v4l drivers to use
unlocked_ioctl.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

"sd" and "err" are too common names to be used in macros for local variables.
Prefix them with an underscore to avoid name clashing.

[mchehab@redhat.com: whitespace cleanups]
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Reviewed-by: NAndy Walls <awalls@md.metrocast.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Add a new framework to handle controls which makes life for driver
developers much easier.

Note that this patch moves some of the control support that used to be in
v4l2-common.c to v4l2-ctrls.c. The tables were copied unchanged. The body
of v4l2_ctrl_query_fill() was copied to a new v4l2_ctrl_fill() function
in v4l2-ctrls.c. This new function doesn't use the v4l2_queryctrl
struct anymore, which makes it more general.

The remainder of v4l2-ctrls.c is all new. Highlights include:

- No need to implement VIDIOC_QUERYCTRL, QUERYMENU, S_CTRL, G_CTRL,
  S_EXT_CTRLS, G_EXT_CTRLS or TRY_EXT_CTRLS in either bridge drivers
  or subdevs. New wrapper functions are provided that can just be plugged in.
  Once everything has been converted these wrapper functions can be removed as well.

- When subdevices are added their controls can be automatically merged
  with the bridge driver's controls.

- Most drivers just need to implement s_ctrl to set the controls.
  The framework handles the locking and tries to be as 'atomic' as possible.

- Ready for the subdev device nodes: the same mechanism applies to subdevs
  and their device nodes as well. Sub-device drivers can make controls
  local, preventing them from being merged with bridge drivers.

- Takes care of backwards compatibility handling of VIDIOC_S_CTRL and
  VIDIOC_G_CTRL. Handling of V4L2_CID_PRIVATE_BASE is fully transparent.
  CTRL_CLASS controls are automatically added.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Add a utility function that can be used to setup the v4l2_device's name
field in a standard manner.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

The name size limit is gone from the driver core, the BUS_ID_SIZE
value will be removed.
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Call v4l2_device_disconnect when the parent of a hotpluggable device
disconnects. This ensures that you do not have a pointer to a device that
is no longer present.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Add a notify callback to v4l2_device to let sub-devices notify their
parent of special events.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Some drivers (e.g. for ISA devices) have no parent device because there
is no associated bus driver. Allow the parent device to be NULL in
those cases when registering v4l2_device.
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

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

Start implementing a proper v4l2 framework as discussed during the
Linux Plumbers Conference 2008.

Introduces v4l2_device (for device instances) and v4l2_subdev (representing
sub-device instances).
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@skynet.be>
Reviewed-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Reviewed-by: NAndy Walls <awalls@radix.net>
Reviewed-by: NDavid Brownell <david-b@pacbell.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>