Re: [RFC PATCH] drm/panel: simple: panel-dpi: use bus-format to set bpc and bus_format

[Maxime Ripard <maxime@cerno.tech>]

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Hi,

Please try to avoid top posting

On Wed, Feb 23, 2022 at 04:25:19PM +0100, Max Krummenacher wrote:
> The goal here is to set the element bus_format in the struct
> panel_desc. This is an enum with the possible values defined in
> include/uapi/linux/media-bus-format.h.
> 
> The enum values are not constructed in a way that you could calculate
> the value from color channel width/shift/mapping/whatever. You rather
> would have to check if the combination of color channel
> width/shift/mapping/whatever maps to an existing value and otherwise
> EINVAL out.
> 
> I don't see the value in having yet another way of how this
> information can be specified and then having to write a more
> complicated parser which maps the dt data to bus_format.

Generally speaking, sending an RFC without explicitly stating what you
want a comment on isn't very efficient.

That being said, what I (and I can only assume Marek) don't like is the
string encoding. Especially when the similar bus-type property uses a
integer with the various available bus options we have.

Having an integer, with a set of defines that you would map to the
proper MEDIA_BUS_* would be more efficient and more elegant.

That being said, the first question that needs to be answered is why
does this have to be in the DT in the first place?

Maxime

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