On Fri, Jan 12, 2018 at 02:58:48AM +0200, Laurent Pinchart wrote: > Hello, > > This patch series addresses a design mistake that dates back from the initial > DU support. Support for the LVDS encoders, which are IP cores separate from > the DU, was bundled in the DU driver. Worse, both the DU and LVDS were > described through a single DT node. > > To fix the, patches 01/10 and 02/10 define new DT bindings for the LVDS > encoders, and deprecate their description inside the DU bindings. To retain > backward compatibility with existing DT, patch 03/10 then patches the device > tree at runtime to convert the legacy bindings to the new ones. > > With the DT side addressed, patch 04/10 then converts the LVDS support code to > a separate bridge driver. After a small fix to the Porter board device tree in > patch 05/10, patches 06/10 to 10/10 then update all the device tree sources to > the new LVDS encoders bindings. > > I decided to go for live DT patching in patch 03/10 because implementing > support for both the legacy and new bindings in the driver would have been > very intrusive, and prevented further cleanups. I'm in a way both proud and > ashamed of that patch that I would call a neat and dirty hack. It was fun to > write perhaps in a similar way that one would enjoy researching and developing > proof-of-concepts for security holes: they're good and bad at the same time. > > Anyway, with this philosophical considerations aside, there were a few > shortcomings in the OF API that I worked around with local code in the driver. > If anyone is interested in performing similar live DT patching I think we > could move some of the code to the OF core. For instance I was surprised > to not find a device node lookup by path function that would start at a > given node instead of the root of the live device tree, and had to write > rcar_du_of_find_node_by_path(). Utility functions to add or modify properties > or to rename nodes could similarly be added. > > Laurent Pinchart (10): > dt-bindings: display: renesas: Add R-Car LVDS encoder DT bindings > dt-bindings: display: renesas: Deprecate LVDS support in the DU > bindings > drm: rcar-du: Fix legacy DT to create LVDS encoder nodes > drm: rcar-du: Convert LVDS encoder code to bridge driver > ARM: dts: porter: Fix HDMI output routing > ARM: dts: r8a7790: Convert to new LVDS DT bindings > ARM: dts: r8a7791: Convert to new LVDS DT bindings > ARM: dts: r8a7793: Convert to new LVDS DT bindings > arm64: dts: renesas: r8a7795: Convert to new LVDS DT bindings > arm64: dts: renesas: r8a7796: Convert to new LVDS DT bindings I understand that there will be a v2 to address review of the non DTS patches. I am marking the DTS patches as "Changes Requested" as they are dependent on the bindings patches from my PoV.
