drm/debugfs: Add kerneldoc

I've decided to not document drm_debugfs_remove_files, it's on the way
out.

The biggest part is a huge todo.rst entry with what all should be
improved.

v2: Nits from Gabriel.

Cc: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170322205401.24897-1-daniel.vetter@ffwll.ch

Documentation/gpu/drm-uapi.rst

@@ -210,6 +210,15 @@ Display CRC Support
 .. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
    :export:
 
+Debugfs Support
+---------------
+
+.. kernel-doc:: include/drm/drm_debugfs.h
+   :internal:
+
+.. kernel-doc:: drivers/gpu/drm/drm_debugfs.c
+   :export:
+
 VBlank event handling
 =====================
 

Documentation/gpu/todo.rst

@@ -272,6 +272,32 @@ This is a really varied tasks with lots of little bits and pieces:
 
 Contact: Daniel Vetter
 
+Clean up the debugfs support
+----------------------------
+
+There's a bunch of issues with it:
+
+- The drm_info_list ->show() function doesn't even bother to cast to the drm
+  structure for you. This is lazy.
+
+- We probably want to have some support for debugfs files on crtc/connectors and
+  maybe other kms objects directly in core. There's even drm_print support in
+  the funcs for these objects to dump kms state, so it's all there. And then the
+  ->show() functions should obviously give you a pointer to the right object.
+
+- The drm_info_list stuff is centered on drm_minor instead of drm_device. For
+  anything we want to print drm_device (or maybe drm_file) is the right thing.
+
+- The drm_driver->debugfs_init hooks we have is just an artifact of the old
+  midlayered load sequence. DRM debugfs should work more like sysfs, where you
+  can create properties/files for an object anytime you want, and the core
+  takes care of publishing/unpuplishing all the files at register/unregister
+  time. Drivers shouldn't need to worry about these technicalities, and fixing
+  this (together with the drm_minor->drm_device move) would allow us to remove
+  debugfs_init.
+
+Contact: Daniel Vetter
+
 Better Testing
 ==============