Re: [PATCH 4/5] dt-bindings: serial: create binding for mcf-uart

[Greg Ungerer <gerg@linux-m68k.org>]

Hi Geert,

On 15/10/26 19:19, Geert Uytterhoeven wrote:
> On Wed, 14 Oct 2026 at 14:56, Greg Ungerer <gerg@linux-m68k.org> wrote:
>> On 14/10/26 21:24, Krzysztof Kozlowski wrote:
>>> On Tue, Oct 13, 2026 at 10:07:02PM +1000, Greg Ungerer wrote:
>>>> Create documentation for a new binding to support the Freescale ColdFire
>>>> UART hardware block. This is found on pretty much all variants of the
>>>> M68K derived Freescale ColdFire family of System-on-Chip devices.
>>>>
>>>> It is not compatible with any other known UARTs.
>>>
>>> You never tested this, so limited review.
>>
>> It is tested. It is working and running on multiple ColdFire platforms.
>>
>>>> Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
> 
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml
> 
>>>> +properties:
>>>> +  compatible:
>>>> +    const: fsl,mcf-uart
>>>
>>> What is the SoC name? MCF? Compatibles must be specific (see writing
>>> bindings doc).
>>
>> Yes. MCF = "Motorola ColdFire". It is the SoC prefix used for naming of all
>> ColdFire parts (which is dozens of variants):
>>
>>    MCF5206
>>    MCF5208
>>    MCF5307
>>    MCF54415
>>    etc
>>
>> Even when Motorola became Freescale they stuck with MCF on all ColdFire parts.
> 
> I guess you want:
> 
>     items:
>       - enum:
>           - fsl,mcf5206
>           - fsl,mcf5208
>           - fsl,mcf5307
>             [...]
>       - const: fsl,mcf-uart
> 
> As no new (possibly incompatible) Coldfire parts will appear, a generic
> fallback looks reasonable to me.

It will be a long list of variants - thanks Freescale. Quite a few of the SoC
parts have sub-parts with different single digits, for example:

    mcf54410, mcf54415, mcf54416, mcf54417, mcf54118

At a quick count I can see about 42 variants. 
I don't mind adding the full list if that is preferred.


> An "mcf" vs. "motorola" vendor prefix might still be a discussion point ;-)

At least they didn't rename the chip part numbers when they renamed the company ;-)

Regards
Greg