From 91a3d6be99e63f6b0a4b2983aef20bd3da2d1a74 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Sat, 6 Jan 2024 17:24:00 -0800 Subject: [PATCH] doc-guide: kernel-doc: tell about object-like macros 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 Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Acked-by: Daniel Vetter Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20240107012400.32587-1-rdunlap@infradead.org --- Documentation/doc-guide/kernel-doc.rst | 45 ++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/Documentation/doc-guide/kernel-doc.rst b/Documentation/doc-guide/kernel-doc.rst index 6ad72ac6861b..d6f7efefea42 100644 --- a/Documentation/doc-guide/kernel-doc.rst +++ b/Documentation/doc-guide/kernel-doc.rst @@ -341,6 +341,51 @@ Typedefs with function prototypes can also be documented:: */ 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 -------------------------------