Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
	drivers/media/v4l2-core/v4l2-async.c:238:1: warning: 'v4l2_async_notifier_unregister' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer.
In this specific case, there's a hard limit imposed by V4L2_MAX_SUBDEVS,
with is currently 128. That means that the buffer size can be up to
128x8 = 1024 bytes (on a 64bits kernel), with is too big for stack.
Worse than that, someone could increase it and cause real troubles.
So, let's use dynamically allocated data, instead.
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>
Reviewed-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

This fixes regression introduced in commit b426b3a6
[media] V4L: Merge struct v4l2_async_subdev_list with struct v4l2_subdev
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

Calling v4l2_async_notifier_unregister() on a notifier that hasn't been
registered leads to a crash. To simplify drivers, make it safe to
unregister a notifier that has not been registered.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

By integrating the v4l2-async API internals a bit more with
the core overall the v4l2-async code becomes a bit simpler
and easier to follow.
Acked-and-tested-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

This is a purely cosmetic change. Since the 'subdev' member
points to an array of subdevs make it more explicit by
renaming to the plural form.
Acked-and-tested-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

Add support for matching by device_node pointer. This allows
the notifier user to simply pass a list of device_node pointers
corresponding to sub-devices.
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

enum v4l2_async_bus_type also selects a method subdevs are matched
in the notification handlers, rename it to v4l2_async_match_type
so V4L2_ASYNC_MATCH_OF entry can be further added for matching by
device tree node pointer.
Acked-and-tested-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

These match_* functions are internal callbacks and are always
invoked only after checking asd->bus_type. So drop redundant
checks in match_i2c() and match_platform() functions.
Acked-and-tested-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

i2c_verify_client() is only available, if I2C is enabled. Fix v4l2-async.c
compilation if I2C is disabled.
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Currently bridge device drivers register devices for all subdevices
synchronously, typically, during their probing. E.g. if an I2C CMOS sensor
is attached to a video bridge device, the bridge driver will create an I2C
device and wait for the respective I2C driver to probe. This makes linking
of devices straight forward, but this approach cannot be used with
intrinsically asynchronous and unordered device registration systems like
the Flattened Device Tree. To support such systems this patch adds an
asynchronous subdevice registration framework to V4L2. To use it respective
(e.g. I2C) subdevice drivers must register themselves with the framework.
A bridge driver on the other hand must register notification callbacks,
that will be called upon various related events.
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>