media: Kconfig: cleanup VIDEO_DEV dependencies

media Kconfig has two entries associated to V4L API:
VIDEO_DEV and VIDEO_V4L2.

On Kernel 2.6.x, there were two V4L APIs, each one with its own flag.
VIDEO_DEV were meant to:
1) enable Video4Linux and make its Kconfig options to appear;
2) it makes the Kernel build the V4L core.

while VIDEO_V4L2 where used to distinguish between drivers that
implement the newer API and drivers that implemented the former one.

With time, such meaning changed, specially after the removal of
all V4L version 1 drivers.

At the current implementation, VIDEO_DEV only does (1): it enables
the media options related to V4L, that now has:

menu "Video4Linux options"
visible if VIDEO_DEV

source "drivers/media/v4l2-core/Kconfig"
endmenu

but it doesn't affect anymore the V4L core drivers.

The rationale is that the V4L2 core has a "soft" dependency
at the I2C bus, and now requires to select a number of other
Kconfig options:

config VIDEO_V4L2
tristate
depends on (I2C || I2C=n) && VIDEO_DEV
select RATIONAL
select VIDEOBUF2_V4L2 if VIDEOBUF2_CORE
default (I2C || I2C=n) && VIDEO_DEV

In the past, merging them would be tricky, but it seems that it is now
possible to merge those symbols, in order to simplify V4L dependencies.

Let's keep VIDEO_DEV, as this one is used on some make *defconfig
configurations.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> # for meson-vdec & meson-ge2d
Acked-by: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: Kconfig files: use select for V4L2 subdevs and MC

There are lots of drivers that only work when the media controller
and/or the V4L2 subdev APIs are present.

Right now, someone need to first enable those APIs before
using those drivers.

Well, ideally, drivers, should, instead *optionally*
depend on it, in order for PC camera drivers to be able to use
them, but nowadays most drivers are UVC cameras, with don't
require a sensor driver.

So, be it.

Let's instead make them select the MEDIA_CONTROLLER and the
SUBDEV API, in order to make easier for people to be able
of enabling them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

staging: add missing SPDX lines to Kconfig files

There are a few remaining drivers/staging/*/Kconfig files that do not
have SPDX identifiers in them. Add the correct GPL-2.0 identifier to
them to make scanning tools happy.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

media: Kconfig files: use the right help coding style

Checkpatch wants to use 'help' instead of '---help---':

WARNING: prefer 'help' over '---help---' for new help texts

Let's change it globally at the media subsystem, as otherwise people
would keep using the old way.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: staging/intel-ipu3: Add imgu top level pci device driver

This patch adds support for the Intel IPU v3 as found
on Skylake and Kaby Lake SoCs.

The driver glues v4l2, css(camera sub system) and other
pieces together to perform its functions, it also loads
the IPU3 firmware binary as part of its initialization.

Signed-off-by: Yong Zhi <yong.zhi@intel.com>
Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>