diff mbox series

[v1,2/8] dt-bindings: display: panel: mipi-dbi-spi: add spi-3wire property

Message ID 20230607115508.2964574-2-l.goehrs@pengutronix.de
State New
Headers
Series [v1,1/8] dt-bindings: display: panel: mipi-dbi-spi: add shineworld lh133k compatible |

Commit Message

Leonard Göhrs June 7, 2023, 11:55 a.m. UTC 
  Some MIPI DBI panels support a three wire mode (clock, chip select,
bidirectional data) that can be used to ask the panel if it is already set
up by e.g. the bootloader and can thus skip the initialization.
This enables a flicker-free boot.

Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
---
 .../devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml   | 2 ++
 1 file changed, 2 insertions(+)

Comments

Conor Dooley June 7, 2023, 5:54 p.m. UTC | #1 
On Wed, Jun 07, 2023 at 01:55:01PM +0200, Leonard Göhrs wrote:
> Some MIPI DBI panels support a three wire mode (clock, chip select,
> bidirectional data) that can be used to ask the panel if it is already set
> up by e.g. the bootloader and can thus skip the initialization.
> This enables a flicker-free boot.
> 
> Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>

Acked-by: Conor Dooley <conor.dooley@microchip.com>

Cheers,
Conor.
Rob Herring June 7, 2023, 10:58 p.m. UTC | #2 
On Wed, Jun 07, 2023 at 09:59:47PM +0200, Noralf Trønnes wrote:
> 
> 
> On 6/7/23 13:55, Leonard Göhrs wrote:
> > Some MIPI DBI panels support a three wire mode (clock, chip select,
> > bidirectional data) that can be used to ask the panel if it is already set
> > up by e.g. the bootloader and can thus skip the initialization.
> > This enables a flicker-free boot.
> > 
> > Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
> > ---
> >  .../devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml   | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
> > index c07da1a9e6288..2f0238b770eba 100644
> > --- a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
> > +++ b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
> > @@ -87,6 +87,8 @@ properties:
> >        Logic level supply for interface signals (Vddi).
> >        No need to set if this is the same as power-supply.
> >  
> > +  spi-3wire: true
> > +
> 
> I don't think this should be added here. spi-cpha and spi-cpol are also
> supported but they are not mentioned. Instead those are documented in
> bindings/spi/spi-controller.yaml. Why they're not documented in
> bindings/spi/spi-peripheral-props.yaml instead which this binding has a
> ref to, I have no idea.

spi-peripheral-props.yaml are properties of the controller in the 
peripheral nodes. spi-cpha and spi-cpol are properties of the device 
which are completely invalid on some devices. We can only check that by 
documenting where they are valid. I think spi-3wire is similar. There 
should be more explanation in the spi-peripheral-props.yaml commit 
history.

Rob
Rob Herring June 7, 2023, 10:59 p.m. UTC | #3 
On Wed, 07 Jun 2023 13:55:01 +0200, Leonard Göhrs wrote:
> Some MIPI DBI panels support a three wire mode (clock, chip select,
> bidirectional data) that can be used to ask the panel if it is already set
> up by e.g. the bootloader and can thus skip the initialization.
> This enables a flicker-free boot.
> 
> Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
> ---
>  .../devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml   | 2 ++
>  1 file changed, 2 insertions(+)
> 

Reviewed-by: Rob Herring <robh@kernel.org>
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
index c07da1a9e6288..2f0238b770eba 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
@@ -87,6 +87,8 @@  properties:
       Logic level supply for interface signals (Vddi).
       No need to set if this is the same as power-supply.
 
+  spi-3wire: true
+
 required:
   - compatible
   - reg