[PATCH 2/5] dt-bindings: display/panel: Expand rotation documentation

[Derek Basehore <dbasehore@chromium.org>]

This adds to the rotation documentation to explain how drivers should
use the property and gives an example of the property in a devicetree
node.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
---
 .../bindings/display/panel/panel.txt          | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/panel.txt b/Documentation/devicetree/bindings/display/panel/panel.txt
index e2e6867852b8..f35d62d933fc 100644
--- a/Documentation/devicetree/bindings/display/panel/panel.txt
+++ b/Documentation/devicetree/bindings/display/panel/panel.txt
@@ -2,3 +2,35 @@ Common display properties
 -------------------------
 
 - rotation:	Display rotation in degrees counter clockwise (0,90,180,270)
+
+Property read from the device tree using of of_drm_get_panel_orientation
+
+The panel driver may apply the rotation at the TCON level, which will
+make the panel look like it isn't rotated to the kernel and any other
+software.
+
+If not, a panel orientation property should be added through the SoC
+vendor DRM code using the drm_connector_init_panel_orientation_property
+function.
+
+Example:
+	panel: panel@0 {
+		compatible = "boe,himax8279d8p";
+		reg = <0>;
+		enable-gpios = <&pio 45 0>;
+		pp33-gpios = <&pio 35 0>;
+		pp18-gpios = <&pio 36 0>;
+		pinctrl-names = "default", "state_3300mv", "state_1800mv";
+		pinctrl-0 = <&panel_pins_default>;
+		pinctrl-1 = <&panel_pins_3300mv>;
+		pinctrl-2 = <&panel_pins_1800mv>;
+		backlight = <&backlight_lcd0>;
+		rotation = <180>;
+		status = "okay";
+
+		port {
+			panel_in: endpoint {
+				remote-endpoint = <&dsi_out>;
+			};
+		};
+	};
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog