[v1,0/3] drm/mediatek: Add support for OF graphs

Message

AngeloGioacchino Del Regno April 4, 2024, 8:16 a.m. UTC

The display IPs in MediaTek SoCs are *VERY* flexible and those support
being interconnected with different instances of DDP IPs (for example,
merge0 or merge1) and/or with different DDP IPs (for example, rdma can
be connected with either color, dpi, dsi, merge, etc), forming a full
Display Data Path that ends with an actual display.

This series was born because of an issue that I've found while enabling
support for MT8195/MT8395 boards with DSI output as main display: the
current mtk_drm_route variations would not work as currently, the driver
hardcodes a display path for Chromebooks, which have a DisplayPort panel
with DSC support, instead of a DSI panel without DSC support.

There are other reasons for which I wrote this series, and I find that
hardcoding those paths - when a HW path is clearly board-specific - is
highly suboptimal. Also, let's not forget about keeping this driver from
becoming a huge list of paths for each combination of SoC->board->disp
and... this and that.

For more information, please look at the commit description for each of
the commits included in this series.

Please don't mind about the missing OVL_ADAPTOR support for OF graphs
in this series: that needs a bit more thinking and a bit more work, and
will come in a second series that will go on top of this a bit later,
as the OF graph support for *at least* the primary display is essential
*right now* to enable support for the MT8195/8395 EVK, Kontron SoM,
Radxa NIO-12L and all of the other non-Chromebook boards to co-exist
with Chromebooks.

Besides, this is also a valid option for MT8188 Chromebooks which might
have different DSI-or-eDP displays depending on the model (as far as I
can see from the mtk_drm_route attempt for this SoC that is already
present in this driver).

This series was tested on MT8195 Cherry Tomato and on MT8395 Radxa
NIO-12L with both hardcoded paths, OF graph support and partially
hardcoded paths (meaning main display through OF graph and external
display hardcoded, because of OVL_ADAPTOR).

AngeloGioacchino Del Regno (3):
  dt-bindings: display: mediatek: Add OF graph support for board path
  dt-bindings: arm: mediatek: mmsys: Add OF graph support for board path
  drm/mediatek: Implement OF graphs support for display paths

 .../bindings/arm/mediatek/mediatek,mmsys.yaml |  23 ++
 .../display/mediatek/mediatek,aal.yaml        |  40 +++
 .../display/mediatek/mediatek,ccorr.yaml      |  21 ++
 .../display/mediatek/mediatek,color.yaml      |  22 ++
 .../display/mediatek/mediatek,dither.yaml     |  22 ++
 .../display/mediatek/mediatek,dpi.yaml        |  25 +-
 .../display/mediatek/mediatek,dsc.yaml        |  24 ++
 .../display/mediatek/mediatek,dsi.yaml        |  27 +-
 .../display/mediatek/mediatek,ethdr.yaml      |  22 ++
 .../display/mediatek/mediatek,gamma.yaml      |  19 ++
 .../display/mediatek/mediatek,merge.yaml      |  23 ++
 .../display/mediatek/mediatek,od.yaml         |  22 ++
 .../display/mediatek/mediatek,ovl-2l.yaml     |  22 ++
 .../display/mediatek/mediatek,ovl.yaml        |  22 ++
 .../display/mediatek/mediatek,postmask.yaml   |  21 ++
 .../display/mediatek/mediatek,rdma.yaml       |  22 ++
 .../display/mediatek/mediatek,ufoe.yaml       |  21 ++
 drivers/gpu/drm/mediatek/mtk_dpi.c            |  16 +-
 drivers/gpu/drm/mediatek/mtk_drm_drv.c        | 255 ++++++++++++++++--
 drivers/gpu/drm/mediatek/mtk_drm_drv.h        |   2 +-
 drivers/gpu/drm/mediatek/mtk_dsi.c            |  10 +-
 21 files changed, 645 insertions(+), 36 deletions(-)