Re: [PATCH v4 00/16] R-Car DU: Convert LVDS code to bridge driver

From: Simon Horman
Date: Wed Feb 21 2018 - 11:39:36 EST


On Wed, Feb 21, 2018 at 01:10:30AM +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 01/16 and 02/16 define new DT bindings for the LVDS
> encoders, and deprecate their description inside the DU bindings. To retain
> backward compatibility with existing DT, patches 03/16 to 08/16 then patch the
> device tree at runtime to convert the legacy bindings to the new ones.
>
> With the DT side addressed, patch 09/16 converts the LVDS support code to a
> separate bridge driver. Patches 11/16 to 16/16 then update all the device tree
> sources to the new DU and LVDS encoders bindings.
>
> I decided to go for live DT patching in patch 08/16 because implementing
> support for both the legacy and new bindings in the driver would have been
> very intrusive, and prevented further cleanups. This version relies more
> heavily on overlays to avoid touching the internals of the OF core compared to
> v2, even if manual fixes to the device tree are still needed.
>
> Compared to v3, this series uses the OF changeset API to update properties
> instead of accessing the internals of the property structure. This removes the
> local implementation of functions to look up nodes by path and update
> properties. In order to do this, I pulled in Pantelis' patch series titled
> "[PATCH v2 0/5] of: dynamic: Changesets helpers & fixes" at Rob's request, and
> rebased it while taking two small review comments into account.
>
> Rob, I'd like this series to be merged in v4.17. As the changeset helpers are
> now a dependency, I'd need you to merge them early (ideally on top of
> v4.16-rc1) and provide a stable branch, or get your ack to merge them through
> Dave's tree if they don't conflict with what you have and will queue for
> v4.17.
>
> This version also drops the small fix to the Porter board device tree that has
> been queued for v4.17 already.
>
> Compared to v2, the biggest change is in patch 03/16. Following Rob's and
> Frank's reviews it was clear that modifying the unflattened DT structure of
> the overlay before applying it wasn't popular. I have thus decided to use one
> overlay source per SoC to move as much of the DT changes to the overlay as
> possible, and only perform manual modifications (that are still needed as some
> of the information is board-specific) on the system DT after applying the
> overlay. As a result the overlay is parsed and applied without being modified.
>
> Compared to v1, this series update the r8a7792 and r8a7794 device tree sources
> and incorporate review feedback as described by the changelogs of individual
> patches.
>
>
> Laurent Pinchart (11):
> 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: r8a7790: Convert to new LVDS DT bindings
> ARM: dts: r8a7791: Convert to new LVDS DT bindings
> ARM: dts: r8a7792: Convert to new DU DT bindings
> ARM: dts: r8a7793: Convert to new LVDS DT bindings
> ARM: dts: r8a7794: Convert to new DU DT bindings
> arm64: dts: renesas: r8a7795: Convert to new LVDS DT bindings
> arm64: dts: renesas: r8a7796: Convert to new LVDS DT bindings

I have marked the dts patches above as deferred as they depend
on the driver changes not to cause a regression. Please repost them
or otherwise ping me once the driver dependencies are present in an rc
release.

I am assuming that the other patches in this series are not targeted
at the renesas tree.

>
> Pantelis Antoniou (5):
> of: dynamic: Add __of_node_dupv()
> of: changesets: Introduce changeset helper methods
> of: changeset: Add of_changeset_node_move method
> of: unittest: changeset helpers
> i2c: demux: Use changeset helpers for clarity

...