Commit 1d31c6fc authored by Rob Herring (Arm)'s avatar Rob Herring (Arm)
Browse files

dt-bindings: writing-schema: Add details on YAML text blocks 



The YAML format has a couple of different forms for multi-line text
blocks which control allowed characters and handling of line-breaks.
Getting this wrong is a common review issue. Either a literal block is
used when there's no formatting needed or a folded/literal block is
not used when there is formatting to maintain.

Add some descriptions of the different forms to point folks to in
reviews.

Reviewed-by: default avatarConor Dooley <conor.dooley@microchip.com>
Reviewed-by: default avatarKrzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20240918195130.2024205-2-robh@kernel.org


Signed-off-by: default avatarRob Herring (Arm) <robh@kernel.org>
parent 29bf3116

Documentation/devicetree/bindings/writing-schema.rst

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@@ -43,6 +43,36 @@ description 
  or device does, standards the device conforms to, and links to datasheets for

  more information.



  The YAML format has several options for defining the formatting of the text

  block. The options are controlled with indicator characters following the key

  (e.g. "description: \|"). The minimum formatting needed for a block should be

  used. The formatting controls can not only affect whether the YAML can be

  parsed correctly, but are important when the text blocks are rendered to

  another form. The options are as follows.



  The default without any indicators is flowed, plain scalar style where single

  line breaks and leading whitespace are stripped. Paragraphs are delimited by

  blank lines (i.e. double line break). This style cannot contain ": " in it as

  it will be interpretted as a key. Any " #" sequence will be interpretted as

  a comment. There's other restrictions on characters as well. Most

  restrictions are on what the first character can be.



  The second style is folded which is indicated by ">" character. In addition

  to maintaining line breaks on double line breaks, the folded style also

  maintains leading whitespace beyond indentation of the first line. The line

  breaks on indented lines are also maintained.



  The third style is literal which is indicated by "\|" character. The literal

  style maintains all line breaks and whitespace (beyond indentation of the

  first line).



  The above is not a complete description of YAML text blocks. More details on

  multi-line YAML text blocks can be found online:



  https://yaml-multiline.info/



  https://www.yaml.info/learn/quote.html



select

  Optional. A json-schema used to match nodes for applying the

  schema. By default, without 'select', nodes are matched against their possible