Re: [PATCH v3 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation

From: Kieran Bingham <kieran.bingham@ideasonboard.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: devicetree@vger.kernel.org,
	Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
	dri-devel@lists.freedesktop.org,
	linux-renesas-soc@vger.kernel.org,
	Jacopo Mondi <jacopo+renesas@jmondi.org>
Subject: Re: [PATCH v3 02/10] dt-bindings: display: bridge: thc63lvd1024: Document dual-link operation
Date: Fri, 7 Jun 2019 23:36:17 +0100	[thread overview]
Message-ID: <17f06c94-a2d3-e159-f89a-02e5a355b7ee@ideasonboard.com> (raw)
In-Reply-To: <20190607223020.GB5110@pendragon.ideasonboard.com>

Hi Laurent,

On 07/06/2019 23:30, Laurent Pinchart wrote:
> Hi Kieran,
> 
> On Fri, Jun 07, 2019 at 11:15:06PM +0100, Kieran Bingham wrote:
>> On 28/05/2019 15:12, Laurent Pinchart wrote:
>>> The THC63LVD1024 LVDS decoder can operate in two modes, single-link or
>>> dual-link. In dual-link mode both input ports are used to carry even-
>>> and odd-numbered pixels separately. Document this in the DT bindings,
>>> along with the related rules governing port and usage.
>>>
>>> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>>> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
>>> Reviewed-by: Rob Herring <robh@kernel.org>
>>> Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
>>> ---
>>>  .../bindings/display/bridge/thine,thc63lvd1024.txt          | 6 ++++++
>>>  1 file changed, 6 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
>>> index 37f0c04d5a28..d17d1e5820d7 100644
>>> --- a/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
>>> +++ b/Documentation/devicetree/bindings/display/bridge/thine,thc63lvd1024.txt
>>> @@ -28,6 +28,12 @@ Optional video port nodes:
>>>  - port@1: Second LVDS input port
>>>  - port@3: Second digital CMOS/TTL parallel output
>>>  
>>> +The device can operate in single-link mode or dual-link mode. In single-link
>>> +mode, all pixels are received on port@0, and port@1 shall not contain any
>>> +endpoint. In dual-link mode, even-numbered pixels are received on port@0 and
>>> +odd-numbered pixels on port@1, and both port@0 and port@1 shall contain
>>> +endpoints.
>>> +
>>
>> Your cover letter details 4 different modes of operation for this part.
>>
>> Do you anticipate the other combinations {Single-in, dual-out; dual-in,
>> dual-out} being supported? Perhaps that would be defined by the relevant
>> endpoints being connected or not ?
> 
> I expect that someone might need those modes at some point, but I
> haven't specified them on purpose, as I don't like writing DT bindings
> that can't be tested. I however expoect that those additional modes can
> be derived from the connected endpoints.
> 
>> You state that in dual-link mode, both port@0, and port@1 shall contain
>> endpoints, so that implies that you only expect to support dual-in with
>> the 'dual-link' property. If that is correct, should it be stated
>> explicitly?
> 
> What do you mean by the 'dual-link' property ? The patch series defines
> no such property.

Aha, my imagination is creating something from all the references to the
word 'dual-link' :-D

Ok - so it is just the existence of the endpoints which will
enable//configure the various modes of operation.

I guess that will become more clear when I get down to the driver patches :)

> 
>> Otherwise,
>>
>> Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
>>
>>>  Example:
>>>  --------
>>>  
> 

-- 
Regards
--
Kieran
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