[PATCH 1/2] dt-bindings: display: bridge: ldb: Implement simple NXP i.MX8M LDB bridge

[Marek Vasut]

On 3/13/22 18:50, Krzysztof Kozlowski wrote:
> On 13/03/2022 18:09, Marek Vasut wrote:
>> On 3/13/22 16:47, Krzysztof Kozlowski wrote:
>>
>> Hi,
>>
>> [...]
>>
>>>> diff --git a/Documentation/devicetree/bindings/display/bridge/nxp,ldb.yaml b/Documentation/devicetree/bindings/display/bridge/nxp,ldb.yaml
>>>> new file mode 100644
>>>> index 0000000000000..a05dd05547836
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/display/bridge/nxp,ldb.yaml
>>>> @@ -0,0 +1,99 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/display/bridge/nxp,ldb.yaml#
>>>
>>> In title, description and commit msg you point this is specific to
>>> i.MX8M, so maybe reflect it in the file name as well.
>>
>> That's how it is so far, however NXP does recycle their IPs quite a bit
>> so I don't want to encode the SoC type into the bindings file name. I do
>> expect them to re-use this bridge somewhere else sooner rather than later.
>>
>> [...]
>>
>> The rest is fixed.
>>
>> [...]
>>
>>>> +examples:
>>>> +  - |
>>>> +    #include <dt-bindings/clock/imx8mp-clock.h>
>>>> +
>>>> +    lvds-ldb {
>>>
>>> Generic node name, so "bridge" or "display-bridge"
>>>
>>>> +        #address-cells = <0>;
>>>> +        #size-cells = <0>;
>>>
>>> Why do you need address and size cells? This will complain if you test
>>> your bindings with proper compatible.
>>
>> Because the subnodes of this bridge have no dimension, so address/size
>> cells = 0.
>>
>> I don't understand the second part about "proper compatible", can you
>> elaborate ?
> 
> You have wrong compatible in example and in bindings, so you do not see
> the error of address/size cells.
> 
> They are also not required in your example, since you do not have unit
> address. Otherwise your lvds-ldb node would be wrong (see its
> address/size cells).
> 
> If you supply address-cells you should see a W=1 warning:
> #address-cells/#size-cells without "ranges" or child "reg" property

Ah, right, both are fixed now. I'll wait a bit for more feedback esp. on 
the bridge driver and send a V2.