Re: [PATCH v2 1/3] dt-bindings: display: mediatek: Add OF graph support for board path

From: AngeloGioacchino Del Regno
Date: Fri Apr 19 2024 - 03:40:34 EST


Il 09/04/24 17:45, Dmitry Baryshkov ha scritto:
On Tue, 9 Apr 2024 at 18:41, AngeloGioacchino Del Regno
<angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:

Il 09/04/24 17:20, Dmitry Baryshkov ha scritto:
On Tue, Apr 09, 2024 at 02:02:09PM +0200, AngeloGioacchino Del Regno wrote:
The display IPs in MediaTek SoCs support being interconnected with
different instances of DDP IPs (for example, merge0 or merge1) and/or
with different DDP IPs (for example, rdma can be connected with either
color, dpi, dsi, merge, etc), forming a full Display Data Path that
ends with an actual display.

The final display pipeline is effectively board specific, as it does
depend on the display that is attached to it, and eventually on the
sensors supported by the board (for example, Adaptive Ambient Light
would need an Ambient Light Sensor, otherwise it's pointless!), other
than the output type.

With the color and gamma being in play, should the configuration be
board-driver or rather use-case driven with the driver being able to
reroute some of the blocks at runtime?


The driver can already set some blocks to "BYPASS MODE" at runtime, meaning
that those will work as simple pass-through, performing *no* processing at
all, so that's addressed from the very beginning.

This doesn't mean that a specific pipeline must always support the "DISP_GAMMA"
or the "DISP_CCOLOR" block(s) alone, or together, or in combination with another
specific block.

I was thinking about slightly different case: do you have enough
colour blocks to drive all outputs or do you have to select them for
the particular output only?

Sorry for the very very very very .. very late reply, your email slipped through
the cracks and I just noticed it.

That depends on the SoC, but generally... no, you have to select them for the
particular output.

There is a restricted set of outputs that support this block, but between this
set, there are still not enough blocks for all of them.


(excuse me, I didn't check the platform details).

You (and me, and everyone else) can't really invest hours of time to check on
how each and every SoC on the planet works - that's normal.

No worries ;-)

Cheers,
Angelo


For any other question, clarification, etc, I'm here :-)

Cheers!


Add support for OF graphs to most of the MediaTek DDP (display) bindings
to add flexibility to build custom hardware paths, hence enabling board
specific configuration of the display pipeline and allowing to finally
migrate away from using hardcoded paths.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>