LinuxLists.cc - [RFC PATCH 1/4] dt-bindings: display: Convert common panel bindings to DT schema

On Thu, Jun 20, 2019 at 3:01 AM Thierry Reding <[email protected]> wrote:
>
> On Wed, Jun 19, 2019 at 03:51:53PM -0600, Rob Herring wrote:
> > Convert the common panel bindings to DT schema consolidating scattered
> > definitions to a single schema file.
> >
> > The 'simple-panel' binding just a collection of properties and not a
> > complete binding itself. All of the 'simple-panel' properties are
> > covered by the panel-common.txt binding with the exception of the
> > 'no-hpd' property, so add that to the schema.
> >
> > As there are lots of references to simple-panel.txt, just keep the file
> > with a reference to panel-common.yaml for now until all the bindings are
> > converted.
> >
> > Cc: Thierry Reding <[email protected]>
> > Cc: Sam Ravnborg <[email protected]>
> > Cc: Maxime Ripard <[email protected]>
> > Cc: Laurent Pinchart <[email protected]>
> > Cc: [email protected]
> > Signed-off-by: Rob Herring <[email protected]>
> > ---
> > Note there's still some references to panel-common.txt that I need to
> > update or just go ahead and convert to schema.
> >
> > .../bindings/display/panel/panel-common.txt | 101 -------------
> > .../bindings/display/panel/panel-common.yaml | 143 ++++++++++++++++++
> > .../bindings/display/panel/panel.txt | 4 -
> > .../bindings/display/panel/simple-panel.txt | 29 +---
> > 4 files changed, 144 insertions(+), 133 deletions(-)
> > delete mode 100644 Documentation/devicetree/bindings/display/panel/panel-common.txt
> > create mode 100644 Documentation/devicetree/bindings/display/panel/panel-common.yaml
>
> I know it was this way before, but perhaps remove the redundant panel-
> prefix while at it?

Sure.

> > diff --git a/Documentation/devicetree/bindings/display/panel/panel-common.yaml b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
> > new file mode 100644
> > index 000000000000..6fe87254edad
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
> > @@ -0,0 +1,143 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/display/panel/panel-common.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Common Properties for Display Panels
> > +
> > +maintainers:
> > + - Thierry Reding <[email protected]>
> > + - Laurent Pinchart <[email protected]>
> > +
> > +description: |
> > + This document defines device tree properties common to several classes of
> > + display panels. It doesn't constitue a device tree binding specification by
> > + itself but is meant to be referenced by device tree bindings.
> > +
> > + When referenced from panel device tree bindings the properties defined in this
> > + document are defined as follows. The panel device tree bindings are
> > + responsible for defining whether each property is required or optional.
> > +
> > +
>
> Are the two blank lines here on purpose?

No.

> The original document had two
> blank lines here, but that was mostly for readability I would guess. The
> YAML format doesn't really need additional formatting for readability,
> so perhaps just remove the extra blank line?
>
> > +properties:
> > + # Descriptive Properties
> > + width-mm:
> > + description: The width-mm and height-mm specify the width and height of the
> > + physical area where images are displayed. These properties are expressed
> > + in millimeters and rounded to the closest unit.
> > +
> > + height-mm:
> > + description: The width-mm and height-mm specify the width and height of the
> > + physical area where images are displayed. These properties are expressed
> > + in millimeters and rounded to the closest unit.
>
> I suppose there's no way in YAML to share the description between both
> the width-mm and height-mm properties? It's a little unfortunate that we
> have to copy, but if there's no better way, guess we'll have to live
> with it.

I could make it a comment instead, but then we loose being able to
parse it. I should probably just reword them to be separate:

"Specifies the height of the physical area where images are displayed.
The property is expressed in millimeters and rounded to the closest
unit."

Also, just realized I need to make these 2 dependencies on either
other (i.e. not valid to only have one).

> > + label:
> > + description: |
> > + The label property specifies a symbolic name for the panel as a
> > + string suitable for use by humans. It typically contains a name inscribed
> > + on the system (e.g. as an affixed label) or specified in the system's
> > + documentation (e.g. in the user's manual).
> > +
> > + If no such name exists, and unless the property is mandatory according to
> > + device tree bindings, it shall rather be omitted than constructed of
> > + non-descriptive information. For instance an LCD panel in a system that
> > + contains a single panel shall not be labelled "LCD" if that name is not
> > + inscribed on the system or used in a descriptive fashion in system
> > + documentation.
> > +
> > + rotation:
> > + description:
> > + Display rotation in degrees counter clockwise (0,90,180,270)
> > + allOf:
> > + - $ref: /schemas/types.yaml#/definitions/uint32
> > + - enum: [ 0, 90, 180, 270 ]
> > +
> > + # Display Timings
> > + panel-timing:
>
> Am I the only one bugged by the redundancy in this property name? What
> else is the timing going to express if not the timing of the panel that
> it's part of. "timing" really would be enough. Anyway, not much we can
> do about it now.

I'm just happy we have a defined name.

Rob

2019-06-20 15:18:28

by Rob Herring (Arm)

[permalink] [raw]

Subject: Re: [RFC PATCH 1/4] dt-bindings: display: Convert common panel bindings to DT schema

On Thu, Jun 20, 2019 at 12:55 AM Sam Ravnborg <[email protected]> wrote:
>
> Hi Rob.
>
> Thanks for starting the conversion of panel bindings to yaml.
>
> On Wed, Jun 19, 2019 at 03:51:53PM -0600, Rob Herring wrote:
> > Convert the common panel bindings to DT schema consolidating scattered
> > definitions to a single schema file.
> >
> > The 'simple-panel' binding just a collection of properties and not a
> > complete binding itself. All of the 'simple-panel' properties are
> > covered by the panel-common.txt binding with the exception of the
> > 'no-hpd' property, so add that to the schema.
> >
> > As there are lots of references to simple-panel.txt, just keep the file
> > with a reference to panel-common.yaml for now until all the bindings are
> > converted.
> Good idea.
>
> >
> > Cc: Thierry Reding <[email protected]>
> > Cc: Sam Ravnborg <[email protected]>
> > Cc: Maxime Ripard <[email protected]>
> > Cc: Laurent Pinchart <[email protected]>
> > Cc: [email protected]
> > Signed-off-by: Rob Herring <[email protected]>
> > ---
> > Note there's still some references to panel-common.txt that I need to
> > update or just go ahead and convert to schema.
> Better let it point to the .yaml variant, so this patchset does not
> depend on too much other bindings to be converted.

There's only 8 files referencing panel-common.txt which was why I was
debating just converting all of them.

> Then we can start the conversion of the remaining panel bindings.
> Any tooling that helps the conversions?

I have a doc2yaml script that helps with some of the boilerplate. It's
in my yaml-bindings-v2 branch[1].

> When this hits upstream I assume all future panel bindings shall be yaml
> based - so we have a few pending contributions that need to do something.

That would be ideal, but not strictly required. For pending things, no
reason to make folks redo things. Requiring schema really depends on
whomever is applying things to run at least 'make dt_binding_check'
before accepting.

>
> For the actual conversion below:
> Acked-by: Sam Ravnborg <[email protected]>

Thanks.

Rob

[1] https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git/log/?h=yaml-bindings-v2

2019-06-20 22:01:57

by Rob Herring (Arm)

[permalink] [raw]

Subject: Re: [RFC PATCH 1/4] dt-bindings: display: Convert common panel bindings to DT schema

On Thu, Jun 20, 2019 at 8:52 AM Rob Herring <[email protected]> wrote:
>
> On Thu, Jun 20, 2019 at 3:01 AM Thierry Reding <[email protected]> wrote:
> >
> > On Wed, Jun 19, 2019 at 03:51:53PM -0600, Rob Herring wrote:
> > > Convert the common panel bindings to DT schema consolidating scattered
> > > definitions to a single schema file.
> > >
> > > The 'simple-panel' binding just a collection of properties and not a
> > > complete binding itself. All of the 'simple-panel' properties are
> > > covered by the panel-common.txt binding with the exception of the
> > > 'no-hpd' property, so add that to the schema.
> > >
> > > As there are lots of references to simple-panel.txt, just keep the file
> > > with a reference to panel-common.yaml for now until all the bindings are
> > > converted.
> > >
> > > Cc: Thierry Reding <[email protected]>
> > > Cc: Sam Ravnborg <[email protected]>
> > > Cc: Maxime Ripard <[email protected]>
> > > Cc: Laurent Pinchart <[email protected]>
> > > Cc: [email protected]
> > > Signed-off-by: Rob Herring <[email protected]>
> > > ---
> > > Note there's still some references to panel-common.txt that I need to
> > > update or just go ahead and convert to schema.
> > >
> > > .../bindings/display/panel/panel-common.txt | 101 -------------
> > > .../bindings/display/panel/panel-common.yaml | 143 ++++++++++++++++++
> > > .../bindings/display/panel/panel.txt | 4 -
> > > .../bindings/display/panel/simple-panel.txt | 29 +---
> > > 4 files changed, 144 insertions(+), 133 deletions(-)
> > > delete mode 100644 Documentation/devicetree/bindings/display/panel/panel-common.txt
> > > create mode 100644 Documentation/devicetree/bindings/display/panel/panel-common.yaml
> >
> > I know it was this way before, but perhaps remove the redundant panel-
> > prefix while at it?
>
> Sure.

On 2nd thought, I prefer it as-is. The reason being the schema
including this file are more readable with:

allOf:
- $ref: panel-common.yaml#

Compared to one of:

$ref: common.yaml#
$ref: /schemas/display/panel/common.yaml#

I suppose we could automagically include a 'common.yaml' file if
existing in the same directory. That's a bigger change though...

Rob