Re: [PATCH] drm: Turn bus flags macros into an enum

[Sam Ravnborg <sam@ravnborg.org>]

Hi Laurent

On Sat, Jan 12, 2019 at 03:10:51AM +0200, Laurent Pinchart wrote:
> This allows nicer kerneldoc with an easy way to reference the enum and
> the values.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  include/drm/drm_connector.h | 108 +++++++++++++++++++++---------------
>  1 file changed, 64 insertions(+), 44 deletions(-)
> 
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 00bb7a74962b..f5ce255a2cb4 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -253,6 +253,68 @@ enum drm_panel_orientation {
>  	DRM_MODE_PANEL_ORIENTATION_RIGHT_UP,
>  };
>  
> +/**
> + * enum drm_bus_flags - bus_flags info for &drm_display_info
> + *
> + * This enum defines signal polarities and clock edge information for signals on
> + * a bus as bitmask flags.
> + *
> + * The clock edge information is conveyed by two sets of symbols,
> + * DRM_BUS_FLAGS_*_DRIVE_\* and DRM_BUS_FLAGS_*_SAMPLE_\*. When this enum is
> + * used to describe a bus from the point of view of the transmitter, the
> + * \*_DRIVE_\* flags should be used. When used from the point of view of the
> + * receiver, the \*_SAMPLE_\* flags should be used. The \*_DRIVE_\* and
> + * \*_SAMPLE_\* flags alias each other, with the \*_SAMPLE_POSEDGE and
> + * \*_SAMPLE_NEGEDGE flags being equal to \*_DRIVE_NEGEDGE and \*_DRIVE_POSEDGE
> + * respectively. This simplifies code as signals are usually sampled on the
> + * opposite edge of the driving edge. Transmitters and receivers may however
> + * need to take other signal timings into account to convert between driving
> + * and sample edges.
> + *
> + * @DRM_BUS_FLAG_DE_LOW:		The Data Enable signal is active low
> + * @DRM_BUS_FLAG_DE_HIGH:		The Data Enable signal is active high
> + * @DRM_BUS_FLAG_PIXDATA_POSEDGE:	Legacy value, do not use
> + * @DRM_BUS_FLAG_PIXDATA_NEGEDGE:	Legacy value, do not use
Could you extend the comment to expalin what there replacements are?
Otherwise we leave it to someone with less understanding of the subject
to find out.
There are 30+ cases we need to fix and we better do it right.

It would also be nice to have the legacy values grouped so they are easier to ignore.


	Sam
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