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Subject[PATCH 1/4] dt-bindings: display: panel: document panel-id
Date
From: Rob Clark <robdclark@chromium.org>

For devices that have one of several possible panels installed, the
panel-id property gives firmware a generic way to locate and enable the
panel node corresponding to the installed panel. Example of how to use
this property:

ivo_panel {
compatible = "ivo,m133nwf4-r0";
panel-id = <0xc5>;
status = "disabled";

ports {
port {
ivo_panel_in_edp: endpoint {
remote-endpoint = <&sn65dsi86_out_ivo>;
};
};
};
};

boe_panel {
compatible = "boe,nv133fhm-n61";
panel-id = <0xc4>;
status = "disabled";

ports {
port {
boe_panel_in_edp: endpoint {
remote-endpoint = <&sn65dsi86_out_boe>;
};
};
};
};

sn65dsi86: bridge@2c {
compatible = "ti,sn65dsi86";

ports {
#address-cells = <1>;
#size-cells = <0>;

port@0 {
reg = <0>;
sn65dsi86_in_a: endpoint {
remote-endpoint = <&dsi0_out>;
};
};

port@1 {
reg = <1>;

sn65dsi86_out_boe: endpoint@c4 {
remote-endpoint = <&boe_panel_in_edp>;
};

sn65dsi86_out_ivo: endpoint@c5 {
remote-endpoint = <&ivo_panel_in_edp>;
};
};
};
};

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
.../bindings/display/panel/panel-common.yaml | 26 +++++++++++++++++++
1 file changed, 26 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel-common.yaml b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
index ef8d8cdfcede..6113319b91dd 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-common.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
@@ -75,6 +75,32 @@ properties:
in the device graph bindings defined in
Documentation/devicetree/bindings/graph.txt.

+ panel-id:
+ description:
+ To support the case where one of several different panels can be installed
+ on a device, the panel-id property can be used by the firmware to identify
+ which panel should have it's status changed to "ok". This property is not
+ used by the HLOS itself.
+
+ For a device with multiple potential panels, a node for each potential
+ should be defined with status = "disabled", and an appropriate panel-id
+ property. The video data producer should be setup with endpoints going to
+ each possible panel. The firmware will find the dt node with a panel-id
+ matching the actual panel installed, and change it's status to "ok".
+
+ The exact method the firmware uses to determine the panel-id of the installed
+ panel is outside the scope of this binding, but a few examples are
+
+ 1) u-boot module reading a value from a u-boot env var
+ 2) EFI driver module reading a value from an EFI variable
+ 3) device specific firmware reading some device specific GPIOs or
+ e-fuse
+
+ The panel-id values are an opaque integer. They can be sparse. The only
+ important thing is that each possible panel in the system has a unique
+ panel-id, and that the values configured in the device's DTB match the
+ values that the firmware is looking for.
+
ddc-i2c-bus:
$ref: /schemas/types.yaml#/definitions/phandle
description:
--
2.23.0
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