[PATCH v2 0/5] drm/ingenic: Add the X1600 LCD controller and the HiBy R1 panel

[Olivier Louvignes]

The display controller of the Ingenic X1600 is not the one ingenic-drm
drives: it fetches frames through descriptors and keeps its interface and
timings in register blocks of their own. It is the X2000's controller
without the composer. This series adds a binding and a driver for it,
then the panel of the HiBy R1, an X1600 audio player: 480x800 parallel
RGB, set up over a 3-wire SPI bus.

The driver covers what the R1 uses and what could be tested: parallel RGB
panels on a 24-bit bus and one full-screen RGB565 plane. The composer,
smart panels and other pixel formats are left out.

Two things come from the vendor kernel rather than the manual. A flip
also writes SRD_CHAIN_START, which the manual doesn't describe for a
running controller; flips without it were not tried. The panel's set-up
sequence is the vendor's too: HiBy calls the panel LG35583, its maker and
controller are unknown, hence the hiby prefix.

Changes in v2, all in 3/5 and all found by the Sashiko review of v1:
- Commits wait for flip_done instead of a vblank before the planes are
  cleaned up. A flip's event waits until the controller reports reading
  the new descriptor, which can be a frame after the vblank that v1's
  default commit_tail waited for, so the old framebuffer could be freed
  while still scanned out.
- A CRTC being enabled sends its event from atomic_enable(), once the
  controller runs; v1 sent it from atomic_flush(), which runs first.
- A plane that is not visible is rejected: the controller always scans
  out a whole frame, so v1 would have read past the end of a small
  framebuffer placed off-screen.
- atomic_disable() returns early when atomic_enable() failed to start
  the pixel clock, instead of touching an unclocked controller.

Tested on a HiBy R1: the fbdev console and a player drawing through
fbdev, blanking and unblanking, 60 page flips in 0.97 s at about 61 Hz,
and the colour order (RGB order swaps red and blue on this panel). For
v2 also: 120 fbdev pans in 1.95 s (one flip per frame, none timing out),
three blank/unblank cycles, and a 64x64 framebuffer set on the primary
plane just past the right edge through SETPLANE, which v1 accepted and
v2 refuses with -EINVAL, while a full-screen one is still accepted.

The X1600 has no device tree upstream yet; its support is being posted
one subsystem at a time. The R1's backlight uses the X1600 PWM driver
posted separately, now at v2:
https://lore.kernel.org/r/20261025191624.9219-1-olivier@xxxxxxxxx

v1: https://lore.kernel.org/r/20261025085816.60405-1-olivier@xxxxxxxxx

Olivier Louvignes (5):
  dt-bindings: vendor-prefixes: Add HiBy
  dt-bindings: display: Add the Ingenic X1600 LCD controller
  drm/ingenic: Add a driver for the X1600 LCD controller
  dt-bindings: display: panel: Add the HiBy LG35583
  drm/panel: Add the HiBy LG35583

 .../bindings/display/ingenic,x1600-lcd.yaml   |  70 ++
 .../bindings/display/panel/hiby,lg35583.yaml  |  71 ++
 .../devicetree/bindings/vendor-prefixes.yaml  |   2 +
 MAINTAINERS                                   |  12 +
 drivers/gpu/drm/Makefile                      |   1 +
 drivers/gpu/drm/ingenic/Kconfig               |  22 +
 drivers/gpu/drm/ingenic/Makefile              |   1 +
 drivers/gpu/drm/ingenic/ingenic-x1600-drm.c   | 744 ++++++++++++++++++
 drivers/gpu/drm/panel/Kconfig                 |  10 +
 drivers/gpu/drm/panel/Makefile                |   1 +
 drivers/gpu/drm/panel/panel-hiby-lg35583.c    | 342 ++++++++
 11 files changed, 1276 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/ingenic,x1600-lcd.yaml
 create mode 100644 Documentation/devicetree/bindings/display/panel/hiby,lg35583.yaml
 create mode 100644 drivers/gpu/drm/ingenic/ingenic-x1600-drm.c
 create mode 100644 drivers/gpu/drm/panel/panel-hiby-lg35583.c


base-commit: cf61bef3801c3c9d0d8c39026b7b2fb242898a3a
-- 
2.39.5