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

[Rob Herring <robh@kernel.org>]

On Thu, Oct 15, 2026 at 11:14:26PM +1000, Greg Ungerer wrote:
> 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

I imagine all of those are just package or marketing differences. 
Freescale did not have the money to tapeout 5 different parts. Just 
using one compatible for all of them is fine. 

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

Just add what you care about or know people use. I imagine that's a much 
smaller subset.

Probably not many users today of the 5272 I worked on which was designed 
for ISDN modems.

Rob