[PATCH] drm: Documentation style guide

[Jani Nikula]

On Wed, 09 Dec 2015, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> Every time I type or review docs this seems a bit different. Try to
> document the common style so we can try to unify at least new docs.
>
> v2: Spelling fixes from Pierre, Laurent and Jani.

Nah, you ignored my comment about "these documentations use American
English". :/

BR,
Jani.

>
> Cc: Pierre Moreau <pierre.morrow at free.fr>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Acked-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> Link: http://patchwork.freedesktop.org/patch/msgid/1449564561-3896-1-git-send-email-daniel.vetter@ffwll.ch
> ---
>  Documentation/DocBook/gpu.tmpl | 37 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
>
> diff --git a/Documentation/DocBook/gpu.tmpl b/Documentation/DocBook/gpu.tmpl
> index 749b8e2f2113..ce4d6f017242 100644
> --- a/Documentation/DocBook/gpu.tmpl
> +++ b/Documentation/DocBook/gpu.tmpl
> @@ -124,6 +124,43 @@
>      <para>
>        [Insert diagram of typical DRM stack here]
>      </para>
> +  <sect1>
> +    <title>Style Guidelines</title>
> +    <para>
> +      For consistency these documentations use American English. Abbreviations
> +      are written as all-uppercase, for example: DRM, KMS, IOCTL, CRTC, and so
> +      on. To aid in reading documentations make full use of the markup
> +      characters kerneldoc provides: @parameter for function paramters, @member
> +      for structure members, &structure to refernce structures and
> +      function() for functions. These all get automatically hyperlinked if
> +      kerneldoc for the referencec objects exists When referencing entries in
> +      function vtables please use -<vfunc(). Note that with kerneldoc does
> +      not support referncing struct members directly, so please add a reference
> +      to the vtable struct somewhere in the same paragraph or at least section.
> +    </para>
> +    <para>
> +      Except in special situations (to separate locked from unlocked variants)
> +      locking requirements for functions aren't documented in the kerneldoc.
> +      Instead locking should be check at runtime using e.g.
> +      <code>WARN_ON(!mutex_is_locked(...));</code>. Since it's much easier to
> +      ignore documentation than runtime noise this provides more value. And on
> +      top of that runtime checks do need to be updated when the locking rules
> +      change, increasing the changes that they're correct. Within the
> +      documentation the locking rules should be explained in the relevant
> +      structures: Either in the comment for the lock explaining what it
> +      protects, or data fields need a note about which lock protects them, or
> +      both.
> +    </para>
> +    <para>
> +      Functions which have a non-<code>void</code> return value should have a
> +      section called "Returns" explaining the expected return values in
> +      different cases an their meanings. Currently there's no consensus whether
> +      that section name should be all upper-case or not, and whether it should
> +      end in a colon or not. Go with the file-local style. Other common section
> +      names are "Notes" with information for dangerous or tricky corner cases,
> +      and "FIXME" where the interface could be cleaned up.
> +    </para>
> +  </sect1>
>    </chapter>
>  
>    <!-- Internals -->

-- 
Jani Nikula, Intel Open Source Technology Center