> > diff --git a/Documentation/devicetree/bindings/endianness/endianness.txt
> b/Documentation/devicetree/bindings/endianness/endianness.txt
> > new file mode 100644
> > index 0000000..64f1d5e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/endianness/endianness.txt
> > @@ -0,0 +1,55 @@
> > +Device-Tree binding for device endianness
> > +
> > +The endianness mode of CPU & Device scenarios:
> > + Index CPU Device
> > + ------------------------
> > + 1 LE LE
> > + 2 LE BE
> > + 3 BE BE
> > + 4 BE LE
> > +
> > +For one device driver, which will run in different scenarios above
> > +on different SoCs using the devicetree, we need one way to simplify
> > +this.
> > +
> > +Required properties:
> > +- [prefix]-endian: this is one string property and must be one
> > + of 'be', 'le' and 'native' if it is present.
>
> What exactly is the prefix?
>
> This file name and file heading implies this is a common endianness
> binding, which it is not. There are many existing bindings that have
> mechanisms for describing the endianness of components, and they have
> settled on a different pattern.
>
> We already have many bindings with {big,little}-endian{,-*} boolean
> properties. It would be better to take that common case and document
> that as the standard way of doing things rather than inventing a
> completely different mechanism.
>
Well, yes, I'll follow your advice.
> > +The endianness mode:
> > + 'le' : device is in little endian mode,
> > + 'be' : device is in big endian mode,
> > + 'native' : device is in the same endian mode with the CPU.
>
> What exactly do you mean by native? A device which always matches the
> endianness of the CPU even if it changes? How common is that?
>
It's originally based the regmap, and the 'native' is make no sense here,
I'll reconstruct this.
> > +
> > +Examples:
> > +Scenario 1 : CPU in LE mode & device in LE mode.
> > +dev: dev@40031000 {
> > + compatible = "name";
> > + reg = <0x40031000 0x1000>;
> > + ...
> > + [prefix]-endian = 'native';
> > +};
>
> If the device is LE, then surely we should describe the device as LE.
> The kernel knows what endianness it is, might choose to change the CPU
> endianness, but regardless can do the right thing. Telling it a device
> is native is useless unless the device changes endianness with the CPU.
>
Yes, you are right.
> > +
> > +Scenario 2 : CPU in LE mode & device in BE mode.
> > +dev: dev@40031000 {
> > + compatible = "name";
> > + reg = <0x40031000 0x1000>;
> > + ...
> > + [prefix]-endian = 'be';
> > +};
> > +
> > +Scenario 3 : CPU in BE mode & device in BE mode.
> > +dev: dev@40031000 {
> > + compatible = "name";
> > + reg = <0x40031000 0x1000>;
> > + ...
> > + [prefix]-endian = 'native';
> > +};
>
> Likewise.
>
> Thanks,
> Mark.
>
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