dt-bindings: display: Convert Allwinner display pipeline to schemas

The Allwinner SoCs have a display engine composed of several controllers
assembled differently depending on the SoC, the number and type of output
they have, and the additional features they provide. A number of those are
supported in Linux, with the matching bindings.

Now that we have the DT validation in place, let's split into separate file
and convert the device tree bindings for those controllers to schemas.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200103152801.47254-1-maxime@cerno.tech

1 files changed, 114 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/display/allwinner,sun4i-a10-display-engine.yaml b/Documentation/devicetree/bindings/display/allwinner,sun4i-a10-display-engine.yaml
new file mode 100644
index 000000000000..944ff2f1cf93
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/allwinner,sun4i-a10-display-engine.yaml
@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/allwinner,sun4i-a10-display-engine.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Allwinner A10 Display Engine Pipeline Device Tree Bindings
+
+maintainers:
+  - Chen-Yu Tsai <wens@csie.org>
+  - Maxime Ripard <mripard@kernel.org>
+
+description: |
+  The display engine pipeline (and its entry point, since it can be
+  either directly the backend or the frontend) is represented as an
+  extra node.
+
+  The Allwinner A10 Display pipeline is composed of several components
+  that are going to be documented below:
+
+  For all connections between components up to the TCONs in the
+  display pipeline, when there are multiple components of the same
+  type at the same depth, the local endpoint ID must be the same as
+  the remote component's index. For example, if the remote endpoint is
+  Frontend 1, then the local endpoint ID must be 1.
+
+  Frontend 0  [0] ------- [0]  Backend 0  [0] ------- [0]  TCON 0
+              [1] --   -- [1]             [1] --   -- [1]
+                    \ /                         \ /
+                     X                           X
+                    / \                         / \
+              [0] --   -- [0]             [0] --   -- [0]
+  Frontend 1  [1] ------- [1]  Backend 1  [1] ------- [1]  TCON 1
+
+  For a two pipeline system such as the one depicted above, the lines
+  represent the connections between the components, while the numbers
+  within the square brackets corresponds to the ID of the local endpoint.
+
+  The same rule also applies to DE 2.0 mixer-TCON connections:
+
+  Mixer 0  [0] ----------- [0]  TCON 0
+           [1] ----   ---- [1]
+                   \ /
+                    X
+                   / \
+           [0] ----   ---- [0]
+  Mixer 1  [1] ----------- [1]  TCON 1
+
+properties:
+  compatible:
+    enum:
+      - allwinner,sun4i-a10-display-engine
+      - allwinner,sun5i-a10s-display-engine
+      - allwinner,sun5i-a13-display-engine
+      - allwinner,sun6i-a31-display-engine
+      - allwinner,sun6i-a31s-display-engine
+      - allwinner,sun7i-a20-display-engine
+      - allwinner,sun8i-a23-display-engine
+      - allwinner,sun8i-a33-display-engine
+      - allwinner,sun8i-a83t-display-engine
+      - allwinner,sun8i-h3-display-engine
+      - allwinner,sun8i-r40-display-engine
+      - allwinner,sun8i-v3s-display-engine
+      - allwinner,sun9i-a80-display-engine
+      - allwinner,sun50i-a64-display-engine
+      - allwinner,sun50i-h6-display-engine
+
+  allwinner,pipelines:
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/phandle-array
+      - minItems: 1
+        maxItems: 2
+    description: |
+      Available display engine frontends (DE 1.0) or mixers (DE
+      2.0/3.0) available.
+
+required:
+  - compatible
+  - allwinner,pipelines
+
+additionalProperties: false
+
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - allwinner,sun4i-a10-display-engine
+          - allwinner,sun6i-a31-display-engine
+          - allwinner,sun6i-a31s-display-engine
+          - allwinner,sun7i-a20-display-engine
+          - allwinner,sun8i-a83t-display-engine
+          - allwinner,sun8i-r40-display-engine
+          - allwinner,sun9i-a80-display-engine
+          - allwinner,sun50i-a64-display-engine
+
+then:
+  properties:
+    allwinner,pipelines:
+      minItems: 2
+
+else:
+  properties:
+    allwinner,pipelines:
+      maxItems: 1
+
+examples:
+  - |
+      de: display-engine {
+          compatible = "allwinner,sun4i-a10-display-engine";
+          allwinner,pipelines = <&fe0>, <&fe1>;
+      };
+
+...