Add HDMI 2.0 support to DW HDMI QP TX

Enable HDMI 2.0 display modes (e.g. 4K@60Hz) on the Synopsys DW HDMI QP
TX controller, as found in Rockchip RK3576 & RK3588 SoCs, by adding SCDC
management for high TMDS clock ratio and scrambling.

Since SCDC state is lost on sink disconnects, the bridge driver needs to
trigger a CRTC reset during connector detection.  To support this, the
series introduces an atomic-aware detect_ctx bridge hook and a
drm_bridge_detect_ctx() helper (patches 1-4), then uses them to
implement the SCDC scrambling feature (patch 5).

Patches 6-8 are minor cleanups in the dw-hdmi-qp and Rockchip platform
drivers.  Patches 9-10 improve HPD handling by deferring IRQ
registration until the connector is fully initialized and restricting
HPD events to the affected connector.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
Changes in v5:
- Added new patches: 1/10, 3/10, 6/10, 7/10, 8/10
- Removed redundant no-op error check in drm_bridge_helper_reset_crtc()
  (patch 1)
- Removed the EDEADLK retry loop from the bridge .detect_ctx() callback,
  as that's already handled in the drm_bridge_detect_ctx() helper or by
  the caller when ctx is provided (patch 2)
- Refactored drm_bridge_detect() to delegate to drm_bridge_detect_ctx()
  and added a WARN_ON for unexpected negative return values (patch 2)
- Split the bridge-connector .detect_ctx() switch into a preparatory
  patch to use cached connector status in .get_modes() (patch 3)
- Improved error handling in SCDC scrambling setup: roll back high TMDS
  clock ratio on scrambling failure, reset scramb_enabled flag on
  set_scramb failure, and add SCDC version read/write error checks
  (patch 5)
- Annotated scramb_enabled with READ_ONCE/WRITE_ONCE for cross-context
  access between modeset paths and the scrambling work item (patch 5)
- Renamed SCDC_MIN_SOURCE_VERSION to SCDC_MAX_SOURCE_VERSION (patch 5)
- Rate limited i2c error messages (patch 6)
- Added missing newlines in dev_err_probe() messages (patch 7)
- Replaced indirect device pointer accesses with local dev variable in
  bind() (patch 8)
- Split the HPD connector restriction (formerly patch 4/4): register HPD
  IRQ after connector setup first (patch 9), then restrict HPD event to
  the affected connector (patch 10); also collected R-b from Heiko
- Rebased onto latest drm-misc-next
- Link to v4: https://lore.kernel.org/r/20260303-dw-hdmi-qp-scramb-v4-0...

Changes in v4:
- Fixed conflicts while rebasing onto latest drm-misc-next
- Link to v3: https://lore.kernel.org/r/20260119-dw-hdmi-qp-scramb-v3-0...

Changes in v3:
- Used drm_bridge_helper_reset_crtc() helper to reset the display
  pipeline and got rid of some boilerplate code (Maxime)
- Rebased onto latest drm-misc-next
- Link to v2: https://lore.kernel.org/r/20260113-dw-hdmi-qp-scramb-v2-0...

Changes in v2:
- Collected Tested-by tags from Diederik and Maud
- Rebased onto latest drm-misc-next
- Ensured the recently introduced 'no-hpd' support for dealing with
  unconnected/repurposed/broken HPD pin is limited to HDMI 1.4 rates
- Link to v1: https://lore.kernel.org/r/20251203-dw-hdmi-qp-scramb-v1-0...

---
Cristian Ciocaltea (10):
      drm/bridge: Remove redundant error check in drm_bridge_helper_reset_crtc()
      drm/bridge: Add detect_ctx hook and drm_bridge_detect_ctx() helper
      drm/bridge-connector: Use cached connector status in .get_modes()
      drm/bridge-connector: Switch to .detect_ctx() for connector detection
      drm/bridge: dw-hdmi-qp: Add HDMI 2.0 SCDC scrambling and high TMDS clock ratio support
      drm/bridge: dw-hdmi-qp: Rate limit i2c read error messages
      drm/rockchip: dw_hdmi_qp: Add missing newlines in dev_err_probe() messages
      drm/rockchip: dw_hdmi_qp: Use local dev variable consistently in bind()
      drm/rockchip: dw_hdmi_qp: Register HPD IRQ after connector setup
      drm/rockchip: dw_hdmi_qp: Restrict HPD event to the affected connector

 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c   | 192 ++++++++++++++++++++++---
 drivers/gpu/drm/display/drm_bridge_connector.c |  75 +++++-----
 drivers/gpu/drm/drm_bridge.c                   |  66 ++++++++-
 drivers/gpu/drm/drm_bridge_helper.c            |   2 -
 drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c |  68 ++++-----
 include/drm/drm_bridge.h                       |  43 +++++-
 6 files changed, 344 insertions(+), 102 deletions(-)
---
base-commit: 03af6c3afc4893988ceed54531f5dde4bebd6024
change-id: 20251203-dw-hdmi-qp-scramb-cdbd8b57ccf9