RE: [PATCH V2] dt-bindings: arm: fsl: Add DHCOM PicoITX and DHCOM DRC02 boards

[Christoph Niedermaier <cniedermaier@dh-electronics.com>]

From: Marek Vasut [mailto:marex@denx.de]
Sent: Wednesday, June 16, 2021 1:33 PM


> On 6/16/21 1:19 PM, Christoph Niedermaier wrote:
>> Send reply also to Rob Herrings +dt email address:
>>
>> From: Rob Herring <robh@kernel.org>
>> Sent: Wednesday, June 2, 2021 9:50 PM
>>
>>> On Tue, May 25, 2021 at 04:30:01PM +0200, Christoph Niedermaier wrote:
>>>> Add DH electronics DHCOM PicoITX and DHCOM DRC02 boards.
>>>>
>>>> Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
>>>> Cc: linux-arm-kernel@lists.infradead.org
>>>> Cc: linux-kernel@vger.kernel.org
>>>> Cc: robh+dt@kernel.org
>>>> Cc: Shawn Guo <shawnguo@kernel.org>
>>>> Cc: kernel@dh-electronics.com
>>>> To: devicetree@vger.kernel.org
>>>> ---
>>>> V2: Remove line with fsl,imx6s on the DRC02 Board
>>>> ---
>>>>   Documentation/devicetree/bindings/arm/fsl.yaml | 12 ++++++++++++
>>>>   1 file changed, 12 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/arm/fsl.yaml b/Documentation/devicetree/bindings/arm/fsl.yaml
>>>> index fce2a8670b49..3c4ff79a3be7 100644
>>>> --- a/Documentation/devicetree/bindings/arm/fsl.yaml
>>>> +++ b/Documentation/devicetree/bindings/arm/fsl.yaml
>>>> @@ -407,6 +407,12 @@ properties:
>>>>             - const: dfi,fs700e-m60
>>>>             - const: fsl,imx6dl
>>>>
>>>> +      - description: i.MX6DL DHCOM PicoITX Board
>>>> +        items:
>>>> +          - const: dh,imx6dl-dhcom-picoitx
>>>> +          - const: dh,imx6dl-dhcom-som
>>>> +          - const: fsl,imx6dl
>>>> +
>>>>         - description: i.MX6DL Gateworks Ventana Boards
>>>>           items:
>>>>             - enum:
>>>> @@ -458,6 +464,12 @@ properties:
>>>>             - const: toradex,colibri_imx6dl          # Colibri iMX6 Module
>>>>             - const: fsl,imx6dl
>>>>
>>>> +      - description: i.MX6S DHCOM DRC02 Board
>>>> +        items:
>>>> +          - const: dh,imx6s-dhcom-drc02
>>>> +          - const: dh,imx6s-dhcom-som
>>>> +          - const: fsl,imx6dl
>>>
>>> fsl,imx6s?
>>
>> In the first version I had here an additional line with "fsl,imx6s",
>> but currently the kernel isn't supporting that compatible. The i.MX6
>> Solo is currently supported by "fsl,imx6dl". So my idea was to add
>> both "fsl,imx6dl" and "fsl,imx6s" to match it maybe on a later kernel
>> version. If there is no match with the Solo now, it will fall back to
>> the i.MX6 DualLite. That is why I had both fsl,imx6s and fsl,imx6dl
>> in that order. On Fabio's advice, I removed the line with "fsl,imx6s"
>> in version 2.
>> Is this what you meant by your comment?
> 
> I didn't notice that at first myself, but I think what Rob means is
> 
> - const: dh,imx6s-dhcom-drc02
> - const: dh,imx6s-dhcom-som
> - const: fsl,imx6dl <------ this should be consistent with the two above
> 
> that is
> 
>   - const: dh,imx6s-dhcom-drc02
>   - const: dh,imx6s-dhcom-som
> -- const: fsl,imx6dl
> +- const: fsl,imx6s
>                ^^^^^
> 
> But that is a bit odd here:
> - The MX6S is MX6DL with one CPU core disabled.
> - The DRC02 device can only house a SOM with MX6S and NOT with MX6DL
> (due to some thermal design consideration or something).
> - The kernel discerns the MX6S/MX6DL automatically based on the number
> of cores it reads from some register, therefore it only has the
> fsl,mx6dl compatible to cover both MX6S and MX6DL.
> So, the closest fallback compatible for this device really is the MX6DL,
> i.e. fsl,imx6dl.
> 
> So I think this patch is correct as-is, no ?

Is this Patch OK?