drm: rcar-du: Add Color Management Module (CMM)

References:
A reference to the v1 cover letter, with some background on the CMM is
available here:
https://lkml.org/lkml/2019/6/6/583
v2:
https://lore.kernel.org/linux-renesas-soc/20190706140746....
v3:
https://lore.kernel.org/linux-renesas-soc/20190825135154....
v4:
https://lore.kernel.org/linux-renesas-soc/20190906135436....

Again, quite a consistent changelog, mostly due to the developments happened on
Ezequiel's VOP unit following Sean's advices.

I here implemented the same, and moved the CMM handling to the crtc being and
enable callbacks. As a result the overall implementation results quite a lot
simplified, mostly on the CMM driver side.

I have dropped tags and acks on the CMM driver and CMM enablement patches in
DU crtc driver because of the number of changes.

A more detailed change log:

- Rebased on renesas-devel-2019-10-07-v5.4-rc4

* Bindings/DT
- Included Rob's comments on the yaml file license and the use of 'OneOf'
  in the compatible property description
- Use the bracketed style suggested by Kieran for the 'renesas,cmm' property
  introduced in patch 2
- Re-order the properties in the SoC DTS files as suggested by Kieran

* CMM/DU
- As anticipated, moved CMM management to the crtc from the atomic commit tail
  helper where it was implemented in v4
  This allow to correctly support resume/suspend and proper ordering of the CMM
  enable and setup operations (enable -before- setup)
- As a consequence the CMM driver is greatly simplified by removing the need
  to cache the LUT table entries provided to cmm_setup() and later re-apply
  them at enable time.
- Better support handling of disabled CMM config option by returning -ENODEV
  at cmm_init() time as suggested by Kieran.

* Testing
I have tested by injecting a color inversion LUT table and enabling/disabling it
every 50 displayed frames:
https://jmondi.org/cgit/kmsxx/log/?h=gamma_lut

CMM functionalities are retained between suspend/resume cycles (tested with
suspend-to-idle) without requiring a re-programming of the LUT tables.

Testing with real world use cases might be beneficial. Rajesh are you still
interested in giving this series a spin?

Laurent, Kieran, could we fast-track review of this and hopefully try to have it
merged for v5.5 ?

Thanks Ezequiel for having suggested me this solution.

Thanks
   j

Jacopo Mondi (8):
  dt-bindings: display: renesas,cmm: Add R-Car CMM documentation
  dt-bindings: display, renesas,du: Document cmms property
  drm: rcar-du: Add support for CMM
  drm: rcar-du: kms: Initialize CMM instances
  drm: rcar-du: crtc: Control CMM operations
  drm: rcar-du: crtc: Register GAMMA_LUT properties
  arm64: dts: renesas: Add CMM units to Gen3 SoCs
  drm: rcar-du: kms: Expand comment in vsps parsing routine

 .../bindings/display/renesas,cmm.yaml         |  67 ++++++
 .../bindings/display/renesas,du.txt           |   5 +
 arch/arm64/boot/dts/renesas/r8a7795.dtsi      |  39 ++++
 arch/arm64/boot/dts/renesas/r8a7796.dtsi      |  31 ++-
 arch/arm64/boot/dts/renesas/r8a77965.dtsi     |  31 ++-
 arch/arm64/boot/dts/renesas/r8a77990.dtsi     |  21 ++
 arch/arm64/boot/dts/renesas/r8a77995.dtsi     |  21 ++
 drivers/gpu/drm/rcar-du/Kconfig               |   7 +
 drivers/gpu/drm/rcar-du/Makefile              |   1 +
 drivers/gpu/drm/rcar-du/rcar_cmm.c            | 198 ++++++++++++++++++
 drivers/gpu/drm/rcar-du/rcar_cmm.h            |  60 ++++++
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c        |  89 ++++++++
 drivers/gpu/drm/rcar-du/rcar_du_crtc.h        |   2 +
 drivers/gpu/drm/rcar-du/rcar_du_drv.h         |   2 +
 drivers/gpu/drm/rcar-du/rcar_du_group.c       |   5 +
 drivers/gpu/drm/rcar-du/rcar_du_group.h       |   2 +
 drivers/gpu/drm/rcar-du/rcar_du_kms.c         |  82 +++++++-
 drivers/gpu/drm/rcar-du/rcar_du_regs.h        |   5 +
 18 files changed, 665 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/renesas,cmm.yaml
 create mode 100644 drivers/gpu/drm/rcar-du/rcar_cmm.c
 create mode 100644 drivers/gpu/drm/rcar-du/rcar_cmm.h

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2.23.0