The R8A7779 DU is split in per-CRTC resources (scan-out engine, blending
unit, timings generator, ...) and device-global resources (start/stop
control, planes, ...) shared between the two CRTCs.

The R8A7790 introduced a third CRTC with its own set of global resources
This would be modeled as two separate DU device instances if it wasn't
for a handful or resources that are shared between the three CRTCs
(mostly related to input and output routing). For this reason the
R8A7790 DU must be modeled as a single device with three CRTCs, two sets
of "semi-global" resources, and a few device-global resources.

Introduce a new rcar_du_group driver-specific object, without any real
counterpart in the DU documentation, that models those semi-global
resources.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

The functions initialize or register all planes, rename them
accordingly.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Move the plane-related fields of struct rcar_du_device to their own
structure.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

The R-Car Display Unit (DU) DRM driver supports both superposition
processors and all eight planes in RGB and YUV formats with alpha
blending.

Only VGA and LVDS encoders and connectors are currently supported.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>