media: staging/imx: Improve pipeline searching

Export find_pipeline_pad(), renaming to imx_media_pipeline_pad(), and
extend its functionality to allow searching for video devices in the
enabled pipeline in addition to sub-devices.

As part of this:

- Rename imx_media_find_mipi_csi2_channel() to
imx_media_pipeline_csi2_channel().

- Remove imx_media_find_upstream_pad(), it is redundant now.

- Rename imx_media_find_upstream_subdev() to imx_media_pipeline_subdev()
with an additional boolean argument for searching upstream or downstream.

- Add imx_media_pipeline_video_device() which is analogous to
imx_media_pipeline_subdev() but searches for video devices.

- Remove imxmd pointer arg from all of the functions above, it was
never used in those functions. With that change the i.MX5/6 CSI,
VDIC, and IC sub-devices no longer require the media_device.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: staging/imx: Switch to sync registration for IPU subdevs

Because the IPU sub-devices VDIC and IC are not present in the
device-tree, platform devices were created for them instead. This
allowed these sub-devices to be added to the media device's async
notifier and registered asynchronously along with the other
sub-devices that do have a device-tree presence (CSI and devices
external to the IPU and SoC).

But that approach isn't really necessary. The IPU sub-devices don't
actually require a backing device (sd->dev is allowed to be NULL).
And that approach can't get around the fact that the IPU sub-devices
are not part of a device hierarchy, which makes it awkward to retrieve
the parent IPU of these devices.

By registering them synchronously, they can be registered from the CSI
async bound notifier, so the init function for them can be given the CSI
subdev, who's dev->parent is the IPU. That is a somewhat cleaner way
to retrieve the parent IPU.

So convert to synchronous registration for the VDIC and IC task
sub-devices, at the time a CSI sub-device is bound. There is no longer
a backing device for them (sd->dev is NULL), but that's ok. Also
set the VDIC/IC sub-device owner as the IPU, so that a reference can
be taken on the IPU module.

Since the VDIC and IC task drivers are no longer platform drivers,
they are now statically linked to imx-media module.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

staging: media: imx: add proper SPDX identifiers on files that did not have them.

There were a few files for the imx media drivers that did not have SPDX
identifiers on them, so fix that up. At the same time, remove the "free
form" text that specified the license of the file, as that is impossible
for any tool to properly parse.

Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>
Cc: linux-media@vger.kernel.org
Acked-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[media] media: imx: Add IC subdev drivers

This is a set of three media entity subdevice drivers for the i.MX
Image Converter:

- Pre-process Router: Takes input frames from CSI0, CSI1, or VDIC.
Two output pads enable either or both of the preprocess tasks
below. If the input is from one of the CSIs, both proprocess task
links can be enabled to process frames from that CSI simultaneously.
If the input is the VDIC, only the Pre-processing Viewfinder task
link can be enabled.

- Pre-processing Encode task: video frames are routed directly from
the CSI and can be scaled, color-space converted, and rotated.
Scaled output is limited to 1024x1024 resolution. Output frames
are routed to the prpenc capture device.

- Pre-processing Viewfinder task: this task can perform the same
conversions as the pre-process encode task, but in addition can
be used for hardware motion compensated deinterlacing. Frames can
come either directly from the CSI or from the VDIC. Scaled output
is limited to 1024x1024 resolution. Output frames are routed to
the prpvf capture device.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>