diff mbox series

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

Message ID 20201124071155.76868-2-tomi.valkeinen@ti.com (mailing list archive)
State New, archived
Headers show
Series drm: add DisplayPort connector | expand

Commit Message

Tomi Valkeinen Nov. 24, 2020, 7:11 a.m. UTC 
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@ti.com>
Cc: Rob Herring <robh+dt@kernel.org>
---
 .../display/connector/dp-connector.yaml       | 55 +++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/connector/dp-connector.yaml

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Comments

Laurent Pinchart Nov. 30, 2020, 10:10 a.m. UTC | #1 
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@ti.com>
> Cc: Rob Herring <robh+dt@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@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.

> +
> +  hpd-gpios:
> +    description: A GPIO line connected to HPD
> +    maxItems: 1
> +
> +  dp-pwr-supply:
> +    description: Power supply for the DP_PWR pin
> +    maxItems: 1
> +
> +  port:
> +    description: Connection to controller providing DP signals

Now that the OF graph schema has landed, could you add the corresponding
$ref ?

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +
> +required:
> +  - compatible
> +  - type
> +  - port
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    connector {
> +        compatible = "dp-connector";
> +        label = "dp0";
> +        type = "full-size";
> +
> +        port {
> +            dp_connector_in: endpoint {
> +                remote-endpoint = <&dp_out>;
> +            };
> +        };
> +    };
> +
> +...
Tomi Valkeinen Nov. 30, 2020, 10:42 a.m. UTC | #2 
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@ti.com>
>> Cc: Rob Herring <robh+dt@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@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
diff mbox series

Patch

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@ti.com>
+
+properties:
+  compatible:
+    const: dp-connector
+
+  label: true
+
+  type:
+    enum:
+      - full-size
+      - mini
+
+  hpd-gpios:
+    description: A GPIO line connected to HPD
+    maxItems: 1
+
+  dp-pwr-supply:
+    description: Power supply for the DP_PWR pin
+    maxItems: 1
+
+  port:
+    description: Connection to controller providing DP signals
+
+required:
+  - compatible
+  - type
+  - port
+
+additionalProperties: false
+
+examples:
+  - |
+    connector {
+        compatible = "dp-connector";
+        label = "dp0";
+        type = "full-size";
+
+        port {
+            dp_connector_in: endpoint {
+                remote-endpoint = <&dp_out>;
+            };
+        };
+    };
+
+...