On 08/04/2017 09:54 AM, Laurent Pinchart wrote:
Hi David,
Thank you for the patch.
On Thursday 03 Aug 2017 17:33:47 David Lechner wrote:
This adds a new binding for Sitronix ST7586 display panels.
Using lego as the vendor prefix in the compatible string because the display
panel I am working with is an integral part of the LEGO MINDSTORMS EV3.
Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
---
.../bindings/display/sitronix,st7586.txt | 26 +++++++++++++++++++
1 file changed, 26 insertions(+)
create mode 100644
Documentation/devicetree/bindings/display/sitronix,st7586.txt
diff --git a/Documentation/devicetree/bindings/display/sitronix,st7586.txt
b/Documentation/devicetree/bindings/display/sitronix,st7586.txt new file
mode 100644
index 0000000..dfb0b7b
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/sitronix,st7586.txt
@@ -0,0 +1,26 @@
+Sitronix ST7586 display panel
+
+Required properties:
+- compatible: "lego,ev3-lcd".
+
+The node for this driver must be a child node of a SPI controller, hence
+all mandatory properties described in ../spi/spi-bus.txt must be specified.
+
+Optional properties:
+- dc-gpios: D/C pin. The presence/absence of this GPIO determines
+ the panel interface operation mode (IF[3:1] pins):
+ - present: IF=011 4-wire 8-bit data serial interface
+ - absent: IF=010 3-wire 9-bit data serial interface
How does this work ? Do you have a single GPIO on your system connected to
IF[1], with IF[3:2] hardwired to 01 ?
LEGO has not made the internals of the display publicly available, so I
cannot say for sure. But I assume that IF[3:1] is hardwired to 011. This
causes pin D1 to assigned to the signal A0, which is what we are calling
the dc gpio here.
If IF[3:1] were hardwired to 010, then pin D1 would be not not used and
there would be no A0 signal.
So, basically, we can infer the state of IF[3:1] by the fact that we
have a dc pin or not.
+- reset-gpios: Reset pin
+- power-supply: A regulator node for the supply voltage.
+- backlight: phandle of the backlight device attached to the panel
+- rotation: panel rotation in degrees counter clockwise (0,90,180,270)
Please use the OF graph DT bindings (a.k.a. ports) to describe the connection
between the panel and its source.
I am afraid that I do not understand this request. What would the source
of the panel be? There is nothing like a SoC LCD controller that is
driving this panel.
+Example:
+ display@0{
+ compatible = "lego,ev3-lcd";
+ reg = <0>;
+ spi-max-frequency = <10000000>;
+ dc-gpios = <&gpio 43 GPIO_ACTIVE_HIGH>;
+ reset-gpios = <&gpio 80 GPIO_ACTIVE_HIGH>;
+ };
--
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