[PATCHv2 3/3] Documentation: DT bindings: Tegra AHB: note base address change

Paul Walmsley paul at pwsan.com
Thu Mar 19 11:46:59 PDT 2015

On Thu, 19 Mar 2015, Stephen Warren wrote:

> We should not document Linux 4.1 as the cut-off. DT bindings are supposed to
> be OS agnostic. While it's practically unlikely, it is entirely possible for
> some other OS to have already implemented support for this binding, and the
> current binding is an ABI. We have no control over if/when any non-Linux code
> is updated to add support for a 0-based offset for existing SoCs, and
> certainly no versions of Linux or any other OS can be updated retro-actively
> except perhaps a few linux-stable versions. We can however write the binding
> in such a way as support for new SoCs requires the new 0-based address, since
> there is no binding specification for those new chips yet, and the time when
> you add the new binding documentation is the first time any OS could possibly
> add conformant support for it.
> In summary, I believe the binding document must state that T20/30/114/124
> require the offset of 4 in reg value, and newer chips require no offset in the
> reg value. We can still always accept either in the Linux kernel going forward
> based on the principle of being lenient re: input data.

That's fine.  I'll send a patch for that.

- Paul

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