Re: [PATCH v7 04/10] drm: Introduce the DP AUX bus

From: Linus Walleij
Date: Sat May 22 2021 - 06:34:45 EST

On Mon, May 17, 2021 at 10:09 PM Douglas Anderson <dianders@xxxxxxxxxxxx> wrote:

> Historically "simple" eDP panels have been handled by panel-simple
> which is a basic platform_device. In the device tree, the panel node
> was at the top level and not connected to anything else.
> Let's change it so that, instead, panels can be represented as being
> children of the "DP AUX bus". Essentially we're saying that the
> hierarchy that we're going to represent is the "control" connections
> between devices. The DP AUX bus is a control bus provided by an eDP
> controller (the parent) and consumed by a device like a panel (the
> child).
> The primary incentive here is to cleanly provide the panel driver the
> ability to communicate over the AUX bus while handling lifetime issues
> properly. The panel driver may want the AUX bus for controlling the
> backlight or querying the panel's EDID.
> The idea for this bus's design was hashed out over IRC [1].
> [1]
> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Lyude Paul <lyude@xxxxxxxxxx>
> Cc: Rajeev Nandan <rajeevny@xxxxxxxxxxxxxx>
> Suggested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>

I like the concept and the general idea behind this, clean and
helpful design.
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>

Linus Walleij