Re: [PATCH 1/3] dt-bindings: fsl: scu: add fallback compatible string for power domain

[Rob Herring <robh+dt@kernel.org>]

On Fri, Jan 11, 2019 at 7:03 AM Shawn Guo <shawnguo@kernel.org> wrote:
>
> On Fri, Jan 11, 2019 at 10:48:21AM +0000, Aisheng Dong wrote:
> > Hi Shawn,
> >
> > > -----Original Message-----
> > > From: Shawn Guo [mailto:shawnguo@kernel.org]
> > > Sent: Friday, January 11, 2019 5:07 PM
> > >
> > > On Fri, Jan 11, 2019 at 05:00:11PM +0800, Shawn Guo wrote:
> > > > On Tue, Dec 18, 2018 at 04:01:20PM +0000, Aisheng Dong wrote:
> > > > > SCU power domain can be used in the same way by IMX8QXP and
> > > IMX8QM SoCs.
> > > > > Let's add a "fsl,scu-pd" fallback compatible string to allow other
> > > > > SoCs to reuse the common part.
> > > >
> > > > This is not the practice we used to match devices with
> > > > compatibilities, i.e. coding the compatible string with the SoC name
> > > > that firstly introduces the device, and use the compatible as fallback for new
> > > SoCs.
> > >
> >
> > This is suggested by Rob that if the future SoCs are likely to be compatible.
> > Then we can use a general fallback compatible string like "fsl,scu-pd".
> > https://patchwork.kernel.org/patch/10644815/
> >
> > From SCU HW protocol point of view, they're indeed compatible.
> > Just varies a bit on the domains numbers.
> > That's why we introduce "fsl,scu-pd".
> > But still keep SoC specific compatible string in case any special tricks
> > to ensure the ABI stability.
> >
> > How do you think?
>
> Unless Rob is against the practice we have been used for long time on
> i.MX, I would keep using it for i.MX8, i.e. instead of introducing a
> generic compatible for fallback, simply falling on the compatible SoC
> specified IP block.

That is certainly my preference and the traditional way to do
compatible in DT, but some reason folks don't like having old SoC
names in their shiny new SoC DT. So either way is fine. But I'd follow
what you do for the rest of i.MX which I guess is what Shawn suggests.

Rob