[PATCH 1/5] dt-bindings: display: panel-dpi: Add bits-per-color property

[Chen-Yu Tsai]

On Tue, Jul 21, 2020 at 5:23 PM Maxime Ripard <maxime at cerno.tech> wrote:
>
> On Mon, Jul 20, 2020 at 08:10:26PM -0600, Rob Herring wrote:
> > On Tue, Jul 14, 2020 at 03:13:01PM +0800, Chen-Yu Tsai wrote:
> > > From: Chen-Yu Tsai <wens at csie.org>
> > >
> > > Some LCD panels do not support 24-bit true color, or 8bits per channel
> > > RGB. Many low end ones only support up to 6 bits per channel natively.
> >
> > This should be implied by the panel's compatible property.
>
> I'm not sure it should, or at least it's not sufficient. Some panels
> while 24 bits capable might only have the higher bits connected to save
> off a couple of pins per color, in which case we should probably
> describe that somehow.

The bus format stuff that was added then removed might be better suited
for what you have in mind. Right now that's put in the simple panel
driver, but it likely doesn't belong there, since the bus format is
also related to the hardware integration, signal routing as you mentioned,
and not just a property of the panel itself.

Nevertheless, what I'm looking for can be achieved using bus format
as well. Given that I have no datasheet for the panel in the device
I'm upstreaming, and only a vague part number to go with, describing
it as a bus format modifier rather than a property of the panel might
be safer.

So I'll just drop the two patches regarding bit depth for now.


ChenYu