On Sun, 7 Jan 2024 at 02:24, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> Since 2014 kernel-doc has supported describing object-like macros
> but it is not documented anywhere. I should have required some
> documentation for it when I merged the patch. :(
>
> There are currently only 3 uses of this (all in DRM headers, in
> include/drm/*.h).
>
> Add object-like macro kernel-doc documentation now so that more may
> know about it and use it.
>
> Fixes: cbb4d3e6510b ("scripts/kernel-doc: handle object-like macros")
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Cc: Jonathan Corbet <corbet@xxxxxxx>
> Cc: linux-doc@xxxxxxxxxxxxxxx
> ---
> v2: Previous attempts to use kernel-doc were for data definitions,
> not macros, so remove that comment.
> Remove a duplicate word in the patch description.
> Add examples.
Randy pointed to this in another thread and also mentioned that
function-like macros are already documented, so this also has my
Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>
> Documentation/doc-guide/kernel-doc.rst | 45 +++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff -- a/Documentation/doc-guide/kernel-doc.rst b/Documentation/doc-guide/kernel-doc.rst
> --- a/Documentation/doc-guide/kernel-doc.rst
> +++ b/Documentation/doc-guide/kernel-doc.rst
> @@ -341,6 +341,51 @@ Typedefs with function prototypes can al
> */
> typedef void (*type_name)(struct v4l2_ctrl *arg1, void *arg2);
>
> +Object-like macro documentation
> +-------------------------------
> +
> +Object-like macros are distinct from function-like macros. They are
> +differentiated by whether the macro name is immediately followed by a
> +left parenthesis ('(') for function-like macros or not followed by one
> +for object-like macros.
> +
> +Function-like macros are handled like functions by ``scripts/kernel-doc``.
> +They may have a parameter list. Object-like macros have do not have a
> +parameter list.
> +
> +The general format of an object-like macro kernel-doc comment is::
> +
> + /**
> + * define object_name - Brief description.
> + *
> + * Description of the object.
> + */
> +
> +Example::
> +
> + /**
> + * define MAX_ERRNO - maximum errno value that is supported
> + *
> + * Kernel pointers have redundant information, so we can use a
> + * scheme where we can return either an error code or a normal
> + * pointer with the same return value.
> + */
> + #define MAX_ERRNO 4095
> +
> +Example::
> +
> + /**
> + * define DRM_GEM_VRAM_PLANE_HELPER_FUNCS - \
> + * Initializes struct drm_plane_helper_funcs for VRAM handling
> + *
> + * This macro initializes struct drm_plane_helper_funcs to use the
> + * respective helper functions.
> + */
> + #define DRM_GEM_VRAM_PLANE_HELPER_FUNCS \
> + .prepare_fb = drm_gem_vram_plane_helper_prepare_fb, \
> + .cleanup_fb = drm_gem_vram_plane_helper_cleanup_fb
> +
> +
> Highlights and cross-references
> -------------------------------
>
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
