[PATCH 0/2] drm/verisilicon: add Nuvoton MA35D1 DCUltra Lite support

[Joey Lu <a0987203069@gmail.com>]

This series adds support for the Verisilicon DCUltra Lite display
controller as integrated in the Nuvoton MA35D1 SoC.

The Verisilicon DC driver and its DT binding were originally written by
Icenowy Zheng <zhengxingda@iscas.ac.cn> for the TH1520 SoC, which
carries a DC8000 IP block.  The present series builds on that foundation
with gratitude to Icenowy for the original work.

The DCUltra Lite is a previous generation of the DC8000 series.  While
the two IPs share a broadly similar register layout, a number of
differences prevent the existing driver from working on the MA35D1
without modification:

  - No chip identity registers: the DCUltra Lite does not expose
    model/revision/customer_id hardware registers, so variant detection
    must come from platform data rather than register reads.

  - No CONFIG_EX commit path: the DC8000 staging registers
    (FB_CONFIG_EX, FB_TOP_LEFT, FB_BOTTOM_RIGHT, FB_BLEND_CONFIG,
    PANEL_CONFIG_EX) are absent; the DCUltra Lite uses enable and reset
    bits in FB_CONFIG (bit 0 / bit 4) for direct framebuffer updates.

  - No PANEL_START register: panel output begins when
    PANEL_CONFIG.RUNNING is set; the DC8000 multi-display sync start
    register at 0x1CCC does not exist.

  - Different IRQ registers: IRQ_STA at 0x147C / IRQ_EN at 0x1480,
    versus the DC8000's IRQ_ACK at 0x0010 / IRQ_EN at 0x0014.

  - Simpler clock/reset topology: two clocks ("core" bus gate and "pix0"
    pixel divider), no driver-managed resets.  The DC8000 requires
    core/axi/ahb clocks and three reset lines.

  - Single display output: no per-output indexing is needed.

  - Smaller register space: max_register 0x2000 vs. DC8000's 0x2544.

Patch 1 extends the verisilicon,dc DT binding to accommodate variants
with flexible clock/reset counts and adds a new sub-schema for
nuvoton,ma35d1-dcu.

Patch 2 introduces the vs_dc_info platform data structure, selects the
correct code paths based on the detected IP family, extends Kconfig for
ARCH_MA35, and wires up the "nuvoton,ma35d1-dcu" OF compatible string.

Both patches have been tested on Nuvoton MA35D1 hardware and are
functioning correctly.

Joey Lu (2):
  dt-bindings: display: verisilicon,dc: generalize for DCUltra Lite
    variant
  drm/verisilicon: add support for Nuvoton MA35D1 DCUltra Lite display
    controller

 .../bindings/display/nuvoton,ma35d1-dcu.yaml  |  94 +++++++++++++
 .../bindings/display/verisilicon,dc.yaml      |  64 +++++----
 drivers/gpu/drm/verisilicon/Kconfig           |   2 +-
 drivers/gpu/drm/verisilicon/vs_bridge.c       |  28 ++--
 drivers/gpu/drm/verisilicon/vs_crtc.c         |  13 +-
 drivers/gpu/drm/verisilicon/vs_dc.c           | 129 ++++++++++++------
 drivers/gpu/drm/verisilicon/vs_dc.h           |   1 +
 drivers/gpu/drm/verisilicon/vs_drm.c          |  16 ++-
 drivers/gpu/drm/verisilicon/vs_hwdb.c         |   2 +-
 drivers/gpu/drm/verisilicon/vs_hwdb.h         |  25 ++++
 .../gpu/drm/verisilicon/vs_primary_plane.c    |  43 +++---
 .../drm/verisilicon/vs_primary_plane_regs.h   |   2 +
 12 files changed, 318 insertions(+), 101 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/nuvoton,ma35d1-dcu.yaml

-- 
2.43.0