Re: [docs] [PATCH] ref-manual: classes.rst: document devicetree.bbclass

[Luca Ceresoli <luca.ceresoli@bootlin.com>]

Hi Quentin,

On Thu, 22 Jun 2023 14:54:13 +0200
Quentin Schulz <quentin.schulz@theobroma-systems.com> wrote:

> Hi Michael, Luca,
> 
> On 4/12/23 21:11, Michael Opdenacker via lists.yoctoproject.org wrote:
> > From: Michael Opdenacker <michael.opdenacker@bootlin.com>
> > 
> > This addresses [YOCTO #15092]
> > 
> > Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> > Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
> > ---
> >   documentation/ref-manual/classes.rst | 43 ++++++++++++++++++++++++++++
> >   1 file changed, 43 insertions(+)
> > 
> > diff --git a/documentation/ref-manual/classes.rst b/documentation/ref-manual/classes.rst
> > index f8172e6b29..79a2bdb69b 100644
> > --- a/documentation/ref-manual/classes.rst
> > +++ b/documentation/ref-manual/classes.rst
> > @@ -580,6 +580,49 @@ add the task at the appropriate place, which is usually after
> >   :ref:`ref-tasks-install`. The class then takes care of
> >   staging the files from :term:`DEPLOYDIR` to :term:`DEPLOY_DIR_IMAGE`.
> >   
> > +.. _ref-classes-devicetree:
> > +
> > +``devicetree``
> > +==============
> > +
> > +The :ref:`ref-classes-devicetree` class allows to build a recipe that compiles
> > +device tree source files that are not in the kernel tree.
> > +
> > +The compilation of out-of-tree device tree sources is the same as the kernel
> > +in-tree device tree compilation process. This includes the ability to include
> > +sources from the kernel such as SoC ``dtsi`` files as well as C header files,
> > +such as ``gpio.h``.
> > +
> > +The :ref:`ref-tasks-compile` task will compile two kinds of files:
> > +
> > +- Regular device tree sources with a ``.dts`` extension.
> > +
> > +- Device tree overlays, detected from the presence of the ``/plugin/;``
> > +  string in the file contents.
> > +
> > +This class behaves in a similar way as the :ref:`ref-classes-kernel-devicetree`
> > +class, also deploying output files into ``/boot/devicetree``. However, this
> > +class stores the deployed device tree binaries into the ``devicetree``
> > +subdirectory.  
> 
> If I'm not mistaken, you're saying the same thing twice.
> 
> I believe :ref:`ref-classes-kernel-devicetree` class puts the dtb in 
> /boot directory by default (KERNEL_DTBDEST which defaults to 
> KERNEL_IMAGEDEST which defaults to boot) while 
> :ref:`ref-classes-devicetree` class puts it into /boot/devicetree/ 
> directory?

Haha, you are perfectly right, I wrote nonsense! :-)

> I think you may have used the comment from the devicetree.bbclass header 
> which is also a bit confusing.

Indeed that was my starting point.

I'm sending an amendment tomorrow.

Thanks for reviewing,
Luca

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com