[PATCH v3 0/2] drm: replace simple display pipe users with atomic helpers

struct drm_simple_display_pipe was meant to simplify simple DRM
drivers, but instead adds an extra wrapper around normal DRM atomic
helper setup. As noted in Documentation/gpu/todo.rst, remaining users
should be converted to regular atomic helpers and stop depending on the
simple-KMS interfaces.

Each patch replaces drm_simple_display_pipe_init() with explicit
primary plane, CRTC and encoder setup, and moves the old simple-pipe
callbacks into regular plane and CRTC helper callbacks named according
to local driver conventions.

The conversions preserve helper behavior that used to be implicit in
drm_simple_kms_helper.c, including plane-state validation, CRTC
primary-plane checks, affected-plane propagation, framebuffer prepare
handling, and existing event/vblank flow where applicable.

Result is less helper indirection and more explicit driver-side atomic
wiring, with no remaining simple-KMS dependency in these drivers.

Changes are build-tested only. No hardware testing has been performed.

This patch is based on drm-next-2026-06-27.

AI usage disclosure:
- AI tools were also used to review the code and suggest code changes for
  the DRM atomic conversion.

Thanks,
Ze Huang

Signed-off-by: Ze Huang <redacted>
---
Changes in v3:
- Add a new preparatory patch to avoid duplicate clk_per enables in
  imx-lcdc pipe update after CRTC enable.
- Use commit-local atomic state in enable/update/check paths.
- Link to v2: https://patch.msgid.link/20260716-drm-simple-kms-removal-v2-1-7e4a6b8528e6@oss.qualcomm.com/

Changes in v2:
- use 'commit' as name of struct drm_atomic_commit in atomic helpers
- improve control flow in *_crtc_helper_atomic_check() and
  *_plane_helper_atomic_check()
- Moved page-flip/vblank event handling out of plane update paths and into
  CRTC atomic_flush(), using atomic_flush and disable paths
- decide clock disable by old crtc state
- add calls to drm_crtc_vblank_on() and drm_crtc_vblank_off() in crtc
  atomic_enable() and atomic_disbale()
- test crtc_state->enable before mode size check
- Link to v1: https://patch.msgid.link/20260705-drm-simple-kms-removal-v1-0-b4e1ca053623@oss.qualcomm.com

---
Ze Huang (2):
      drm/imx/lcdc: avoid duplicate clk_per enable
      drm/imx: replace struct drm_simple_display_pipe with regular atomic helpers

 drivers/gpu/drm/imx/lcdc/imx-lcdc.c | 263 ++++++++++++++++++++++++++----------
 1 file changed, 190 insertions(+), 73 deletions(-)
---
base-commit: 3696d07837d1df13a5603d77f667685e7dfb3c53
change-id: 20260704-drm-simple-kms-removal-01a031c6a129

Best regards,
-- 
Ze Huang [off-list ref]