dt-bindings: display: convert Arm HDLCD to DT schema

ARM HDLCD

This is a display controller found on several development platforms produced

by ARM Ltd and in more modern of its' Fast Models. The HDLCD is an RGB

streamer that reads the data from a framebuffer and sends it to a single

digital encoder (DVI or HDMI).

Required properties:

  - compatible: "arm,hdlcd"

  - reg: Physical base address and length of the controller's registers.

  - interrupts: One interrupt used by the display controller to notify the

    interrupt controller when any of the interrupt sources programmed in

    the interrupt mask register have activated.

  - clocks: A list of phandle + clock-specifier pairs, one for each

    entry in 'clock-names'.

  - clock-names: A list of clock names. For HDLCD it should contain:

      - "pxlclk" for the clock feeding the output PLL of the controller.

Required sub-nodes:

  - port: The HDLCD connection to an encoder chip. The connection is modeled

    using the OF graph bindings specified in

    Documentation/devicetree/bindings/graph.txt.

Optional properties:

  - memory-region: phandle to a node describing memory (see

    Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt) to be

    used for the framebuffer; if not present, the framebuffer may be located

    anywhere in memory.

Example:

/ {

	...

	hdlcd@2b000000 {

		compatible = "arm,hdlcd";

		reg = <0 0x2b000000 0 0x1000>;

		interrupts = <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>;

		clocks = <&oscclk5>;

		clock-names = "pxlclk";

		port {

			hdlcd_output: endpoint@0 {

				remote-endpoint = <&hdmi_enc_input>;

			};

		};

	};

	/* HDMI encoder on I2C bus */

	i2c@7ffa0000 {

		....

		hdmi-transmitter@70 {

			compatible = ".....";

			reg = <0x70>;

			port@0 {

				hdmi_enc_input: endpoint {

					remote-endpoint = <&hdlcd_output>;

				};

				hdmi_enc_output: endpoint {

					remote-endpoint = <&hdmi_1_port>;

				};

			};

		};

	};

	hdmi1: connector@1 {

		compatible = "hdmi-connector";

		type = "a";

		port {

			hdmi_1_port: endpoint {

				remote-endpoint = <&hdmi_enc_output>;

			};

		};

	};

	...

};

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

%YAML 1.2

---

$id: http://devicetree.org/schemas/display/arm,hdlcd.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Arm HDLCD display controller binding

maintainers:

  - Liviu Dudau <Liviu.Dudau@arm.com>

  - Andre Przywara <andre.przywara@arm.com>

description:

  The Arm HDLCD is a display controller found on several development platforms

  produced by ARM Ltd and in more modern of its Fast Models. The HDLCD is an

  RGB streamer that reads the data from a framebuffer and sends it to a single

  digital encoder (DVI or HDMI).

properties:

  compatible:

    const: arm,hdlcd

  reg:

    maxItems: 1

  interrupts:

    maxItems: 1

  clock-names:

    const: pxlclk

  clocks:

    maxItems: 1

    description: The input reference for the pixel clock.

  memory-region:

    maxItems: 1

    description:

      Phandle to a node describing memory to be used for the framebuffer.

      If not present, the framebuffer may be located anywhere in memory.

  iommus:

    maxItems: 1

  port:

    $ref: /schemas/graph.yaml#/properties/port

    unevaluatedProperties: false

    description:

      Output endpoint of the controller, connecting the LCD panel signals.

additionalProperties: false

required:

  - compatible

  - reg

  - interrupts

  - clocks

  - port

examples:

  - |

    hdlcd@2b000000 {

        compatible = "arm,hdlcd";

        reg = <0x2b000000 0x1000>;

        interrupts = <0 85 4>;

        clocks = <&oscclk5>;

        clock-names = "pxlclk";

        port {

            hdlcd_output: endpoint {

                remote-endpoint = <&hdmi_enc_input>;

            };

        };

    };

    /* HDMI encoder on I2C bus */

    i2c {

        #address-cells = <1>;

        #size-cells = <0>;

        hdmi-transmitter@70 {

            compatible = "nxp,tda998x";

            reg = <0x70>;

            port {

                hdmi_enc_input: endpoint {

                    remote-endpoint = <&hdlcd_output>;

                };

            };

        };

    };

...