[U-Boot] [PATCH] dm: Update README.txt to clarify device tree usage

[Simon Glass]

Hi Tom,

On 31 August 2018 at 09:59, Tom Rini <trini at konsulko.com> wrote:
> In the section about Device Trees add a paragraph at the end that
> clarifies how we decide of a tree is valid or not.  We say that all
> bindings must either be in the specification (link provided) or in our
> device-tree-bindings directory.  We say that most of these come from the
> Linux Kernel and as such some design decisions are made for us already,
> but that in most cases we wish to retain compatibility.
>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Bin Meng <bmeng.cn at gmail.com>
> Signed-off-by: Tom Rini <trini at konsulko.com>
> ---
>  doc/driver-model/README.txt | 9 +++++++++
>  1 file changed, 9 insertions(+)
>

Reviewed-by: Simon Glass <sjg at chromium.org>

nits below

> diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt
> index d6fa5c485793..e949ff63bae4 100644
> --- a/doc/driver-model/README.txt
> +++ b/doc/driver-model/README.txt
> @@ -449,6 +449,15 @@ The driver model tree is intended to mirror that of the device tree. The
>  root driver is at device tree offset 0 (the root node, '/'), and its
>  children are the children of the root node.
>
> +In order for a device tree to be valid, the content must be correct with
> +respect to either device tree specification
> +(https://www.devicetree.org/specifications/) or the device tree bindings that
> +are found in the doc/device-tree-bindings directory.  When not U-Boot specific

When not U-Boot-specific,

> +the bindings in this directory tend to come from the Linux Kernel.  As such
> +certain design decisions may have been made already for us in terms of how
> +specific devices are described and bound.  In most circumstances we wish to
> +retain compatibility without additional changes being made to the device tree
> +source files.
>
>  Declaring Uclasses
>  ------------------
> --
> 2.7.4
>

Regards,
Simon