Thread (41 messages) 41 messages, 4 authors, 2026-01-23

Re: [PATCH v4 05/25] drm/tilcdc: Convert legacy panel binding via DT overlay at boot time

From: "Luca Ceresoli" <luca.ceresoli@bootlin.com>
Date: 2026-01-19 16:18:19
Also in: dri-devel, linux-devicetree, linux-omap, lkml

On Fri Jan 16, 2026 at 6:02 PM CET, Kory Maincent (TI.com) wrote:
To maintain backward compatibility while removing the deprecated
tilcdc_panel driver, add a tilcdc_panel_legacy subdriver that converts
the legacy "ti,tilcdc,panel" devicetree binding to the standard
panel-dpi binding at early boot.

The conversion uses an embedded device tree overlay that is applied and
modified during subsys_initcall. The process:

- Apply embedded overlay to create a tilcdc-panel-dpi node with
  port/endpoint connections to the LCDC
- Copy all properties from the legacy panel node to the new
  tilcdc-panel-dpi node
- Copy display-timings from the legacy panel
- Convert legacy panel-info properties (invert-pxl-clk, sync-edge) to
  standard display timing properties (pixelclk-active, syncclk-active)
- Disable the legacy panel by removing its compatible property to
  prevent the deprecated driver from binding

The result is a standard tilcdc-panel-dpi node with proper endpoints and
timing properties, allowing the DRM panel infrastructure to work with
legacy devicetrees without modification.

Other legacy panel-info properties are not migrated as they consistently
use default values across all mainline devicetrees and can be hardcoded
in the tilcdc driver.

This feature is optional via CONFIG_DRM_TILCDC_PANEL_LEGACY and should
only be enabled for systems with legacy devicetrees containing
"ti,tilcdc,panel" nodes.

Suggested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://lore.kernel.org/all/1d9a9269-bfda-4d43-938b-2df6b82b9369@ideasonboard.com/ (local)
Signed-off-by: Kory Maincent (TI.com) <kory.maincent@bootlin.com>
---
Looks very good now, thanks for the improvements!

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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