[Patch v2 3/6] dt-bindings: display/ti: Add plane binding to dispc node

[Benoit Parrot]

Currently all available display pipelines (i.e. plane) and output port
resources are exposed to user-space. In some cases it is needed to be
able to restrict which resources are actually visible from user-space.
Also in cases where a display wider than 2048 pixels is to be supported
more than one video pipeline is needed. In this case the 2nd hardware
pipeline needed is not visible to user space applications.

These video pipeline definitions must be statically defined so that
the number of visible pipelines does not change from the user-space
perspective.

In order to allow this we are adding an optional 'plane' sub-node to
the generic DISPC node.

Signed-off-by: Benoit Parrot <bparrot at ti.com>
---
 .../devicetree/bindings/display/ti/ti,omap-dss.txt | 65 ++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/ti/ti,omap-dss.txt b/Documentation/devicetree/bindings/display/ti/ti,omap-dss.txt
index 249e588d7865..2dd411cb5a83 100644
--- a/Documentation/devicetree/bindings/display/ti/ti,omap-dss.txt
+++ b/Documentation/devicetree/bindings/display/ti/ti,omap-dss.txt
@@ -28,6 +28,36 @@ Optional properties:
 - max-memory-bandwidth: Input memory (from main memory to dispc) bandwidth limit
 			in bytes per second
 
+Optional Subnode:
+- plane: Child node(s) which defines which video planes are available to
+	the system. If at least one plane child node is defined then
+	only planes defined by these nodes will be available to the system.
+	Plane nodes must be sequential starting with reg = <0> as DT parsing
+	will stop on the first missing numbered node.
+	This means if plane #1 is defined but plane #0 is not then it will
+	be as if none of the plane nodes were defined.
+
+	Each plane node contains the following properties:
+	Required properties:
+	- reg:       Used to identify the plane
+	- video-pipelines: One or two HW pipeline number(s).
+		When 2 numbers are present this indicates a virtual wide
+		plane composed of two physical planes intended to be used
+		when the display is larger then the capacity of a
+		single plane i.e. wider than 2048 pixels.
+		The first number in the pair will dictate the capabilities
+		of the plane. This means that for proper
+		operation the virtual plane should be composed of HW
+		planes of the same capabilities.
+		If GFX pipeline is used in a virtual plane it should be
+		specified first, otherwise unexpected behavior would
+		be encountered.
+	Optional property:
+	- video-outputs:  One or more HW output number(s).
+		Describe the list of video output on which this plane
+		is available. If this node is not present then the
+		plane will be available on all available video output.
+
 Video Ports
 -----------
 
@@ -216,3 +246,38 @@ OMAP HDMI --(HDMI)--> TPD12S015 --(HDMI)--> HDMI Connector
 		};
 	};
 };
+
+A short example on how to define a virtual plane configuration
+to enable wide display support.
+Here we define:
+- plane#0 to be the HW pipeline #0 (i.e. GFX pipeline)
+	  only available on video output #0
+- plane#1 to be a virtual wide plane composed of HW pipeline #1 and #2
+	  (i.e. VID1 & VID2) available on video output #0 & #1
+- plane#2 to be the HW pipeline #3 (i.e. VID3 pipeline)
+	  only available on video output #0
+
+&dss {
+        dispc at 58001000 {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                plane at 0 {
+                        reg = <0>;
+                        video-pipelines = <0>;
+                        video-outputs = <0>;
+                };
+
+                plane at 1 {
+                        reg = <1>;
+                        video-pipelines = <1 2>;
+                        video-outputs = <0 1>;
+                };
+
+                plane at 2 {
+                        reg = <2>;
+                        video-pipelines = <3>;
+                        video-outputs = <0>;
+                };
+        };
+};
-- 
2.9.0