linux-kernel - Re: How delete node or property in overlayd dts?

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Message-ID: <CAL_JsqLV5d5cL3o3Dx=--zGD37c5O09rL9AXyRFmceTfBHt3Zg@mail.gmail.com>
Date:   Fri, 17 Aug 2018 11:47:48 -0600
From:   Rob Herring <robh+dt@...nel.org>
To:     zbsdta@...il.com, Frank Rowand <frowand.list@...il.com>
Cc:     devicetree@...r.kernel.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: How delete node or property in overlayd dts?

On Tue, Aug 14, 2018 at 7:26 PM Frank Rowand <frowand.list@...il.com> wrote:
>
> On 08/14/18 07:46, 张波 wrote:
> > /delete-node/ /delete-prop/ could be used in dtsi files without device
> > tree overlay.
> >
> > but with device tree overlay,  /delete-node/ and  /delete-prop/ are not work.
> > How to delete property and node in overlay dts?
> >
> > for example,
> > in basel.dts have following node
> > node1 {
> >     property1;
> >     property3;
> >     node2 {
> >         property2;
> >     }
> > }
> >
> > in overlay.dts as following
> >  node1 {
> >     /delete-property/ property1;
> >     /delete-node/ node2;
> > }
> >
> > after overlay, property1 and node2 is not deleted.
> >
>
> The /delete-node/ and /delete-prop/ directives are only used by the
> dtc compiler within a single compilation.
>
> There is nothing in the format of a devicetree blob to represent the
> notion of deleting a property or a node.
>
> You can not delete a property or a node in an overlay dtb.

Though you can add/override 'status' with 'status = "disabled";' which
should be treated very similar to a node not being present. I say
similar because it's a source of bugs for the OS to fail to pay
attention to status property.

Rob