dt-bindings: display: Add Renesas SH-Mobile LCDC bindings

Add device tree bindings for the LCD Controller (LCDC) found in Renesas
SuperH SH-Mobile and ARM SH/R-Mobile SOCs.

Based on a plain text prototype by Laurent Pinchart.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/6d0a053502abd6555e9a6cbe055e1bdc3329999d.1694767208.git.geert+renesas@glider.be

Documentation/devicetree/bindings/display/renesas,shmobile-lcdc.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/renesas,shmobile-lcdc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas SH-Mobile LCD Controller (LCDC)
+
+maintainers:
+  - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
+  - Geert Uytterhoeven <geert+renesas@glider.be>
+
+properties:
+  compatible:
+    enum:
+      - renesas,r8a7740-lcdc # R-Mobile A1
+      - renesas,sh73a0-lcdc  # SH-Mobile AG5
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    minItems: 1
+    maxItems: 5
+    description:
+      Only the functional clock is mandatory.
+      Some of the optional clocks are model-dependent (e.g. "video" (a.k.a.
+      "vou" or "dv_clk") is available on R-Mobile A1 only).
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: fck
+      - enum: [ media, lclk, hdmi, video ]
+      - enum: [ media, lclk, hdmi, video ]
+      - enum: [ media, lclk, hdmi, video ]
+      - enum: [ media, lclk, hdmi, video ]
+
+  power-domains:
+    maxItems: 1
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: LCD port (R-Mobile A1 and SH-Mobile AG5)
+        unevaluatedProperties: false
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: HDMI port (R-Mobile A1 LCDC1 and SH-Mobile AG5)
+        unevaluatedProperties: false
+
+      port@2:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: MIPI-DSI port (SH-Mobile AG5)
+        unevaluatedProperties: false
+
+    required:
+      - port@0
+
+    unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - power-domains
+  - ports
+
+additionalProperties: false
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,r8a7740-lcdc
+    then:
+      properties:
+        ports:
+          properties:
+            port@2: false
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,sh73a0-lcdc
+    then:
+      properties:
+        ports:
+          required:
+            - port@1
+            - port@2
+
+examples:
+  - |
+    #include <dt-bindings/clock/r8a7740-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    lcd-controller@fe940000 {
+        compatible = "renesas,r8a7740-lcdc";
+        reg = <0xfe940000 0x4000>;
+        interrupts = <GIC_SPI 177 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&mstp1_clks R8A7740_CLK_LCDC0>,
+                 <&cpg_clocks R8A7740_CLK_M3>, <&lcdlclk0_clk>,
+                 <&vou_clk>;
+        clock-names = "fck", "media", "lclk", "video";
+        power-domains = <&pd_a4lc>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+
+                lcdc0_rgb: endpoint {
+                };
+            };
+        };
+    };

MAINTAINERS

@@ -7035,6 +7035,7 @@ M:	Geert Uytterhoeven <geert+renesas@glider.be>
 L:	dri-devel@lists.freedesktop.org
 L:	linux-renesas-soc@vger.kernel.org
 S:	Supported
+F:	Documentation/devicetree/bindings/display/renesas,shmobile-lcdc.yaml
 F:	drivers/gpu/drm/renesas/shmobile/
 F:	include/linux/platform_data/shmob_drm.h