[PATCH RESEND v3 1/2] dt-bindings: dp-connector: add binding for DisplayPort connector

[Tomi Valkeinen]

On 30/11/2020 12:10, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Tue, Nov 24, 2020 at 09:11:54AM +0200, Tomi Valkeinen wrote:
>> Add binding for DisplayPort connector. A few notes:
>>
>> * Similar to hdmi-connector, it has hpd-gpios as an optional property,
>>   as the HPD could also be handled by, e.g., the DP bridge.
>>
>> * dp-pwr-supply, which provides 3.3V on DP_PWR pin, is optional, as it
>>   is not strictly required: standard DP cables do not even have the pin
>>   connected.
>>
>> * Connector type. Full size and mini connectors are identical except for
>>   the connector size and form, so I believe there is no functional need
>>   for this property. But similar to 'label' property, it might be used
>>   to present information about the connector to the userspace.
>>
>> * No eDP. There's really no "eDP connector", as it's always a custom
>>   made connection between the DP and the DP panel, although the eDP spec
>>   does offer a few suggested pin setups. So possibly there is no need for
>>   edp-connector binding, but even if there is, I don't want to guess what
>>   it could look like, and could it be part of the dp-connector binding.
>>
>> * No DP++. I'm not familiar with DP++. DP++ might need an i2c bus added
>>   to the bindings.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
>> Cc: Rob Herring <robh+dt at kernel.org>
>> ---
>>  .../display/connector/dp-connector.yaml       | 55 +++++++++++++++++++
>>  1 file changed, 55 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/display/connector/dp-connector.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/display/connector/dp-connector.yaml b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
>> new file mode 100644
>> index 000000000000..b5fc3e52899e
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/connector/dp-connector.yaml
>> @@ -0,0 +1,55 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/display/connector/dp-connector.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: DisplayPort Connector
>> +
>> +maintainers:
>> +  - Tomi Valkeinen <tomi.valkeinen at ti.com>
>> +
>> +properties:
>> +  compatible:
>> +    const: dp-connector
>> +
>> +  label: true
>> +
>> +  type:
>> +    enum:
>> +      - full-size
>> +      - mini
> 
> I wonder if "full" would be better than "full-size" to match "mini". Up
> to you.

The DP spec (and e.g. wikipedia) uses "full-size" and "mini". Well, the spec mostly uses "mDP",
which is explained to mean "Mini DisplayPort". And full-size is used as "full-size DP".

E.g. "The plug on either end may be a full-size DP plug or an mDP plug."

We could use mDP here, but I think "mini" is more commonly used. And if we use mDP for mini, maybe
we should use DP for the full-size. But then it's maybe a bit confusing.

So I think "full-size" and "mini" match best to the spec and are still obvious for the human reader.

 Tomi

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