lkml.org 
[lkml]   [2023]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1 3/6] dt-bindings: display: bridge: toshiba,tc358768: add parallel input mode
On Mon, Apr 03, 2023 at 04:01:17PM -0500, Rob Herring wrote:
> On Fri, Mar 31, 2023 at 11:40:01AM +0200, Francesco Dolcini wrote:
> > On Fri, Mar 31, 2023 at 10:48:15AM +0200, Krzysztof Kozlowski wrote:
> > > On 30/03/2023 11:59, Francesco Dolcini wrote:
> > > > From: Francesco Dolcini <francesco.dolcini@toradex.com>
> > > >
> > > > Add new toshiba,input-rgb-mode property to describe the actual signal
> > > > connection on the parallel RGB input interface.
> > > >
> > > > Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
> > > > ---
> > > > .../bindings/display/bridge/toshiba,tc358768.yaml | 15 +++++++++++++++
> > > > 1 file changed, 15 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/display/bridge/toshiba,tc358768.yaml b/Documentation/devicetree/bindings/display/bridge/toshiba,tc358768.yaml
> > > > index 8f22093b61ae..2638121a2223 100644
> > > > --- a/Documentation/devicetree/bindings/display/bridge/toshiba,tc358768.yaml
> > > > +++ b/Documentation/devicetree/bindings/display/bridge/toshiba,tc358768.yaml
> > > > @@ -42,6 +42,21 @@ properties:
> > > > clock-names:
> > > > const: refclk
> > > >
> > > > + toshiba,input-rgb-mode:
> > > > + description: |
> > > > + Parallel Input (RGB) Mode.
> > > > +
> > > > + RGB inputs (PD[23:0]) color arrangement as documented in the datasheet
> > > > + and in the table below.
> > > > +
> > > > + 0 = R[7:0], G[7:0], B[7:0]
> > >
> > > RGB888?
> >
> > Or anything else - like a RGB666 - just connecting to GND the unused
> > pins.
>
> If the bridge is configured for RGB666, then that's fine. If not, the
> unused pins should be driven with either the MSB of each component.
> Otherwise, you'd can't fully saturate the colors.

> > > > + 1 = R[1:0], G[1:0], B[1:0], R[7:2], G[7:2], B[7:2]
> > > > + 2 = 8’b0, R[4:0], G[5:0], B[4:0]
> > >
> > > Isn't this RGB565?
> > >
> > > Don't we have already properties like this? e.g. colorspace?
> >
> > It's not really the colorspace this property.
> >
> > tc358768 is a parallel RGB to DSI bridge, it has 24 bit parallel input
> > line.
> >
> > The way this lines are connected is configurable with this parameter, if you
> > look at mode 0 and 1 they all allow to have a RGB888 or a RGB666 or a
> > RGB565 mapping. This just configure some internal mux, it's not strictly
> > about the RGB mode.
>
> This is the same as other cases. There's a need for describing the
> interface. It keeps coming up and I keep saying to go create something
> common.

I am not aware of other discussion on the topic, do you have any pointer
I can look at?

What I'd like to re-iterate here once more is that this configuration is
about how the external 24-bit parallel RGB lines are mapped withing this
bridge.

It's not mapping the linux media bus format (e.g. not
MEDIA_BUS_FMT_RBG888_1X24 or alike).

This bridge allow for a limited set of combination (3) as described in
this binding.

Francesco

\
 
 \ /
  Last update: 2023-04-03 23:11    [W:0.064 / U:0.860 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site