drm/rockchip: support gamma control on RK3399

This extends the Rockchip VOP driver to support setting the gamma LUT on the RK3399 SoC. Previously, the driver supported gamma control for the RK3288 only. On the RK3399 the method for updating the LUT is slightly different. This implementation was based on the code and description from the vendor kernel [1].

The RK3399 also has the address resources for the VOP general registers and the gamma LUT located adjacent to each other, not on either side of the IOMMU address as on the RK3288, but for simplicity this series follows the existing DT binding which requires the gamma LUT as a second address resource.

This should enable gamma control and "night mode" on all RK3399-based devices such as the Pinebook Pro, it has been tested using the "redshift" app and GNOME's "Night Light" feature on a RockPro64 SBC. The changes should not affect RK3288 gamma support using the existing code path, testing on RK3288 would be welcome.

Changes from v1: Moved the vop_crtc_gamma_set call to the end of vop_crtc_atomic_enable after the clocks and CRTC are enabled; otherwise VOP regs are written to before the VOP's clocks are enabled which is a no-no and can cause a hang if re-enabling the CRTC after gamma has been set.

Hugh Cole-Baker (3):
drm/rockchip: define gamma registers for RK3399 drm/rockchip: support gamma control on RK3399
arm64: dts: rockchip: enable gamma control on RK3399

 arch/arm64/boot/dts/rockchip/rk3399.dtsi    |   4 +-
 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 105 +++++++++++++-------
 drivers/gpu/drm/rockchip/rockchip_drm_vop.h |   2 +
 drivers/gpu/drm/rockchip/rockchip_vop_reg.c |  24 ++++-
 drivers/gpu/drm/rockchip/rockchip_vop_reg.h |   1 +
 5 files changed, 98 insertions(+), 38 deletions(-)

2.24.3 (Apple Git-128)