Message-ID: <20230103064615.5311-1-a-bhatia1@ti.com>
Date:   Tue, 3 Jan 2023 12:16:11 +0530
From:   Aradhya Bhatia <a-bhatia1@...com>
To:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Tomi Valkeinen <tomba@...nel.org>,
        Jyri Sarha <jyri.sarha@....fi>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Maxime Ripard <maxime@...no.tech>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Guo Ren <guoren@...nel.org>
CC:     DRI Development List <dri-devel@...ts.freedesktop.org>,
        Devicetree List <devicetree@...r.kernel.org>,
        Linux Kernel List <linux-kernel@...r.kernel.org>,
        Linux RISC-V List <linux-riscv@...ts.infradead.org>,
        Linux ARM Kernel List <linux-arm-kernel@...ts.infradead.org>,
        Linux Mediatek List <linux-mediatek@...ts.infradead.org>,
        Linux C-SKY Arch List <linux-csky@...r.kernel.org>,
        Nishanth Menon <nm@...com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Rahul T R <r-ravikumar@...com>,
        Devarsh Thakkar <devarsht@...com>,
        Jai Luthra <j-luthra@...com>,
        Jayesh Choudhary <j-choudhary@...com>,
        Aradhya Bhatia <a-bhatia1@...com>
Subject: [RFC PATCH 0/4] dt-bindings: Introduce dual-link panels & panel-vendors

Hi all,

Microtips Technology Solutions USA, and Lincoln Technology Solutions are
2 display panel vendors, and the first 2 patches add their vendor
prefixes.

The fourth patch, simply introduces the new compatible for the generic
dual-link panels in the panel-lvds driver. This new compatible is based
from a new DT binding added in the third patch explained below.

The third patch introduces a dt-binding for generic dual-link LVDS
panels. These panels do not have any documented constraints, except for
their timing characteristics. Further, these panels have 2 pixel-sinks.
In a dual-link connection between an LVDS encoder and the panel, one
sink accepts the odd set of LVDS pixels and the other, the even set.

A lot of this has been based from the Advantech,idk-2121wr dual-link
panel[1] and Maxime's patches for generic LVDS panels[2] (which are
single-link by default.) and the discussions that happened before they
were finally merged.

Below are some notes and points that I want to bring forward.

  - The advantech,idk-2121wr panel binding uses 2 boolean properties
    dual-link-odd/even-pixels, to signify which port sink is being used
    for which set of LVDS pixels. I too have added similar support and
    introduced constraints around those properties, so as to not break
    the ABI... but I believe there is a better way to achieve this.

    A "pixel-type" enum property could be introduced in their stead,
    which can accept one of the 2 options <dual-lvds-odd-pixels> or
    <dual-lvds-even-pixels>.

    This method, in my opinion, is more accurate and cleaner to
    implement in the bindings as well.

    If this does sound a better I can push out a new revision where the
    driver supports both these methods (to not break the ABI) and the
    advantech,2121wr panel can remain as an exception.


  - As an alternative to the previous point, if that method is not
    preferred for some reason, the advantech,2121wtr panel binding
    could then be merged in the panel-dual-lvds binding as part of
    future work.


  - Another tweak, I am looking forward to do as part of future work and
    would like all your comments is to introduce driver-based
    implementation of the panel timing parameters, like it is with
    "panel-simple". The driver can then support both the panel-timing
    sources (DT node or hard-coded driver structure) and the binding
    can remove this from the "required" section.

Thank you!

[1]: https://patchwork.freedesktop.org/patch/357122/
[2]: https://patchwork.freedesktop.org/patch/471228/

Aradhya Bhatia (4):
  dt-bindings: vendor-prefixes: Add microtips
  dt-bindings: vendor-prefixes: Add lincolntech
  dt-bindings: panel: Introduce dual-link LVDS panel
  drm: panel-lvds: Introduce dual-link panels

 .../display/panel/panel-dual-lvds.yaml        | 157 ++++++++++++++++++
 .../devicetree/bindings/vendor-prefixes.yaml  |   4 +
 MAINTAINERS                                   |   1 +
 drivers/gpu/drm/panel/panel-lvds.c            |   1 +
 4 files changed, 163 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/panel/panel-dual-lvds.yaml

-- 
2.39.0

Powered by blists - more mailing lists