[PATCH 00/10] drm/bridge: handle refcounting for bridge-only callers of drm_of_find_panel_or_bridge()

[Luca Ceresoli]

This series converts all the bridge-only callers of the deprecated
drm_of_find_panel_or_bridge() API to a new, simpler API that handles bridge
refcounting.

== Series description

 * The first patch introduces of_drm_get_bridge_by_endpoint() as a
   replacement for bridge-only calls to drm_of_find_panel_or_bridge(); the
   new function is simpler and returns a refcounted bridge
 * The following patches convert all bridge-only users to the new API
 * The last patch forbids new bridge-only calls to
   drm_of_find_panel_or_bridge()

== Grand plan

This is part of the work to support hotplug of DRM bridges. The grand plan
was discussed in [0].

Here's the work breakdown (➜ marks the current series):

 1. ➜ add refcounting to DRM bridges struct drm_bridge,
      based on devm_drm_bridge_alloc()
    A. ✔ add new alloc API and refcounting (v6.16)
    B. ✔ convert all bridge drivers to new API (v6.17)
    C. ✔ kunit tests (v6.17)
    D. ✔ add get/put to drm_bridge_add/remove() + attach/detach()
         and warn on old allocation pattern (v6.17)
    E. ➜ add get/put on drm_bridge accessors
       1. ✔ drm_bridge_chain_get_first_bridge(), add cleanup action (v6.18)
       2. ✔ drm_bridge_get_prev_bridge() (v6.18)
       3. ✔ drm_bridge_get_next_bridge() (v6.19)
       4. ✔ drm_for_each_bridge_in_chain() (v6.19)
       5. ✔ drm_bridge_connector_init (v6.19)
       6. … protect encoder bridge chain with a mutex
       7. ➜ of_drm_find_bridge
          a. ✔ add of_drm_get_bridge() (v7.0),
               convert basic direct users (v7.0-v7.1)
          b. ✔ convert direct of_drm_get_bridge() users, part 2 (v7.0)
          c. ✔ convert direct of_drm_get_bridge() users, part 3 (v7.0)
          d. ✔… convert direct of_drm_get_bridge() users, part 4
                (some v7.1, some pending)
          e. ➜ convert bridge-only drm_of_find_panel_or_bridge() users
       8. drm_of_find_panel_or_bridge, *_of_get_bridge
       9. ✔ enforce drm_bridge_add before drm_bridge_attach (v6.19)
    F. ✔ debugfs improvements
       1. ✔ add top-level 'bridges' file (v6.16)
       2. ✔ show refcount and list lingering bridges (v6.19)
 2. … handle gracefully atomic updates during bridge removal
    A. ✔ Add drm_bridge_enter/exit() to protect device resources (v7.0)
    B. … protect private_obj removal from list
    C. ✔ Add drm_bridge_clear_and_put() (v7.1)
 3. … DSI host-device driver interaction
 4. ✔ removing the need for the "always-disconnected" connector
 5. … Migrate i.MX LCDIF driver to bridge-connector
 6.   DRM bridge hotplug
    A.   Bridge hotplug management in the DRM core
    B.   Device tree description

[0] https://lore.kernel.org/lkml/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@xxxxxxxxxxx/#t

Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>
---
Luca Ceresoli (10):
      drm/bridge: add of_drm_get_bridge_by_endpoint()
      drm/msm/hdmi: switch to of_drm_get_bridge_by_endpoint()
      drm/hisilicon/kirin: switch to of_drm_get_bridge_by_endpoint()
      drm/bridge: chrontel-ch7033: switch to of_drm_get_bridge_by_endpoint()
      drm/bridge: lontium-lt9611uxc: switch to of_drm_get_bridge_by_endpoint()
      drm/bridge: lt9611: switch to of_drm_get_bridge_by_endpoint()
      drm/bridge: adv7511: switch to of_drm_get_bridge_by_endpoint()
      drm/bridge: lt8713sx: switch to of_drm_get_bridge_by_endpoint()
      drm: zynqmp_dp: switch to of_drm_get_bridge_by_endpoint()
      drm: of: forbid bridge-only calls to drm_of_find_panel_or_bridge()

 drivers/gpu/drm/bridge/adv7511/adv7511.h     |  1 -
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c |  8 ++---
 drivers/gpu/drm/bridge/chrontel-ch7033.c     | 24 +++++++--------
 drivers/gpu/drm/bridge/lontium-lt8713sx.c    |  7 ++---
 drivers/gpu/drm/bridge/lontium-lt9611.c      |  5 ++-
 drivers/gpu/drm/bridge/lontium-lt9611uxc.c   |  5 ++-
 drivers/gpu/drm/drm_bridge.c                 | 46 ++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_of.c                     | 26 ++++++++--------
 drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c |  4 +--
 drivers/gpu/drm/msm/hdmi/hdmi.c              |  3 +-
 drivers/gpu/drm/xlnx/zynqmp_dp.c             | 10 +++---
 include/drm/drm_bridge.h                     |  9 ++++++
 12 files changed, 97 insertions(+), 51 deletions(-)
---
base-commit: f9ef69563cc82e908e1ce84fd135d3290fb65cde
change-id: 20260410-drm-bridge-alloc-getput-panel_or_bridge-42501b38eaad

Best regards,
--  
Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>