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In-Reply-To: <35e85643-b23c-4958-bb8c-f9536bc8d864@axentia.se>
From:   Rob Herring <robh@kernel.org>
Date:   Fri, 28 Dec 2018 11:40:47 -0600
Message-ID: <CAL_JsqJgJ-+NpOJkEAYhjF-3_vaX+y1fO6Q5CPQRe9ptzfuMQA@mail.gmail.com>
Subject: Re: [PATCH v2 1/3] dt-bindings: display: bridge: fork out ti,ds90c185
 from lvds-transmitter
To:     Peter Rosin <peda@axentia.se>
Cc:     Peter Rosin <peda@lysator.liu.se>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        David Airlie <airlied@linux.ie>,
        Mark Rutland <mark.rutland@arm.com>,
        Archit Taneja <architt@codeaurora.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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On Thu, Dec 27, 2018 at 4:54 PM Peter Rosin <peda@axentia.se> wrote:
>
> On 2018-12-27 22:27, Rob Herring wrote:
> > On Wed, Dec 19, 2018 at 02:04:47PM +0100, Peter Rosin wrote:
> >> From: Peter Rosin <peda@axentia.se>
> >>
> >> DS90C185 has a shutdown pin which does not fit in the lvds-transmitter
> >> binding, which is meant to be generic.
> >>
> >> The sister chip DS90C187 is similar to DS90C185, describe it here as well.
> >>
> >> Signed-off-by: Peter Rosin <peda@axentia.se>
> >> ---
> >>  .../bindings/display/bridge/lvds-transmitter.txt   |  8 +---
> >>  .../bindings/display/bridge/ti,ds90c185.txt        | 55 ++++++++++++++++++++++
> >>  2 files changed, 56 insertions(+), 7 deletions(-)
> >>  create mode 100644 Documentation/devicetree/bindings/display/bridge/ti,ds90c185.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt b/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt
> >> index 50220190c203..fd39ad34c383 100644
> >> --- a/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt
> >> +++ b/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt
> >> @@ -22,13 +22,7 @@ among others.
> >>
> >>  Required properties:
> >>
> >> -- compatible: Must be one or more of the following
> >> -  - "ti,ds90c185" for the TI DS90C185 FPD-Link Serializer
> >> -  - "lvds-encoder" for a generic LVDS encoder device
> >> -
> >> -  When compatible with the generic version, nodes must list the
> >> -  device-specific version corresponding to the device first
> >> -  followed by the generic version.
> >> +- compatible: Must be "lvds-encoder"
> >>
> >>  Required nodes:
> >>
> >> diff --git a/Documentation/devicetree/bindings/display/bridge/ti,ds90c185.txt b/Documentation/devicetree/bindings/display/bridge/ti,ds90c185.txt
> >> new file mode 100644
> >> index 000000000000..a13e778503e6
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/display/bridge/ti,ds90c185.txt
> >> @@ -0,0 +1,55 @@
> >> +Texas Instruments FPD-Link (LVDS) Serializer
> >> +--------------------------------------------
> >> +
> >> +The DS90C185 and DS90C187 are low-power serializers for portable
> >> +battery-powered applications that reduces the size of the RGB
> >> +interface between the host GPU and the display.
> >> +
> >> +Required properties:
> >> +
> >> +- compatible: Should be
> >> +  "ti,ds90c185", "lvds-encoder"  for the TI DS90C185 FPD-Link Serializer
> >> +  "ti,ds90c187", "lvds-encoder"  for the TI DS90C187 FPD-Link Serializer
> >> +
> >> +Optional properties:
> >> +
> >> +- pwdn-gpios: Power down control GPIO (the PDB pin, active-low)
> >
> > powerdown-gpios is the standard name.
>
> The lvds-encoder driver handles this binding, and that driver incidentally
> also implements the thine,thc63lvdm83d binding which already has a
> pwdn-gpios property. Should the thine,thc63lvdm83d binding be updated and
> the driver be made to support both properties?
>
> Since the lvds-encoder driver never had support for the pwdn-gpios (at least
> not upstream) I suppose there is also the option to simply go with
> powerdown-gpios as you suggest and not bother with support for the
> pwdn-gpios property.

It is probably safe to just change it given it is not used in any dts
nor supported in the driver.

Rob