Re: [PATCH v3 2/5] dt-bindings: auxdisplay: Add Titan Micro Electronics TM1628

[Heiner Kallweit <hkallweit1@xxxxxxxxx>]

On 24.02.2022 22:30, Rob Herring wrote:
> On Thu, Feb 24, 2022 at 2:56 PM Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote:
>>
>> On 24.02.2022 21:22, Rob Herring wrote:
>>> On Wed, Feb 23, 2022 at 06:59:31PM +0100, Heiner Kallweit wrote:
>>>> Add a YAML schema binding for TM1628 auxdisplay
>>>> (7/11-segment LED) controller.
>>>>
>>>> This patch is partially based on previous work from
>>>> Andreas Färber <afaerber@xxxxxxx>.
>>>>
>>>> Co-Developed-by: Andreas Färber <afaerber@xxxxxxx>
>>>> Signed-off-by: Andreas Färber <afaerber@xxxxxxx>
>>>> Co-Developed-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
>>>> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
>>>> ---
>>>> v3:
>>>> - fix remaining YAML issues
>>>> - use Co-Developed-by
>>>> ---
>>>>  .../bindings/auxdisplay/titanmec,tm1628.yaml  | 92 +++++++++++++++++++
>>>>  1 file changed, 92 insertions(+)
>>>>  create mode 100644 Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml b/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml
>>>> new file mode 100644
>>>> index 000000000..2a1ef692c
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/auxdisplay/titanmec,tm1628.yaml
>>>> @@ -0,0 +1,92 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/auxdisplay/titanmec,tm1628.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Titan Micro Electronics TM1628 LED controller
>>>> +
>>>> +maintainers:
>>>> +  - Andreas Färber <afaerber@xxxxxxx>
>>>> +  - Heiner Kallweit <hkallweit1@xxxxxxxxx>
>>>> +
>>>> +allOf:
>>>> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    const: titanmec,tm1628
>>>> +
>>>> +  reg:
>>>> +    maxItems: 1
>>>> +
>>>
>>>> +  grid:
>>>> +    description:
>>>> +      Mapping of display digit position to grid number.
>>>> +      This implicitly defines the display size.
>>>> +    $ref: /schemas/types.yaml#/definitions/uint8-array
>>>> +    minItems: 1
>>>> +    maxItems: 7
>>>> +
>>>> +  segment-mapping:
>>>> +    description:
>>>> +      Mapping of 7 segment display segments A-G to bit numbers 1-12.
>>>> +    $ref: /schemas/types.yaml#/definitions/uint8-array
>>>> +    minItems: 7
>>>> +    maxItems: 7
>>>
>>> Are these properties useful for any 7 segment display or specific to
>>> this controller?
>>>
>> Both are controller-specific. E.g. the functionally similar driver
>> ht16k33 uses different properties.
> 
> Then they both need a vendor prefix.
> 
OK, will add the prefix. Thanks for the hint.

>>> The commit msg mentions 11 segment display. Does this need to be?:
>>>
>>> oneOf:
>>>   - minItems: 7
>>>     maxItems: 7
>>>   - minItems: 11
>>>     maxItems: 11
>>>
>> The controller would be able to drive 11 segments, but the driver
>> supports 7 segments only (at least for now). Therefore a 11 segment
>> display can be used, but only the 7 segment part will be active.
>> All devices with this controller I've seen and heard of have
>> 7 segment displays.
> 
> Bindings should be complete, not just what a particular version of a
> driver supports. However, if all known h/w is just 7 seg, then it is
> fine.
> 
> Rob