dt-bindings: display: Convert tpo,tpg110 panel to DT schema

TPO TPG110 Panel

================

This panel driver is a component that acts as an intermediary

between an RGB output and a variety of panels. The panel

driver is strapped up in electronics to the desired resolution

and other properties, and has a control interface over 3WIRE

SPI. By talking to the TPG110 over SPI, the strapped properties

can be discovered and the hardware is therefore mostly

self-describing.

       +--------+

SPI -> |  TPO   | -> physical display

RGB -> | TPG110 |

       +--------+

If some electrical strap or alternate resolution is desired,

this can be set up by taking software control of the display

over the SPI interface. The interface can also adjust

for properties of the display such as gamma correction and

certain electrical driving levels.

The TPG110 does not know the physical dimensions of the panel

connected, so this needs to be specified in the device tree.

It requires a GPIO line for control of its reset line.

The serial protocol has line names that resemble I2C but the

protocol is not I2C but 3WIRE SPI.

Required properties:

- compatible : one of:

  "ste,nomadik-nhk15-display", "tpo,tpg110"

  "tpo,tpg110"

- grestb-gpios : panel reset GPIO

- width-mm : see display/panel/panel-common.txt

- height-mm : see display/panel/panel-common.txt

The device needs to be a child of an SPI bus, see

spi/spi-bus.txt. The SPI child must set the following

properties:

- spi-3wire

- spi-max-frequency = <3000000>;

as these are characteristics of this device.

The device node can contain one 'port' child node with one child

'endpoint' node, according to the bindings defined in

media/video-interfaces.txt. This node should describe panel's video bus.

Example

-------

panel: display@0 {

	compatible = "tpo,tpg110";

	reg = <0>;

	spi-3wire;

	/* 320 ns min period ~= 3 MHz */

	spi-max-frequency = <3000000>;

	/* Width and height from data sheet */

	width-mm = <116>;

	height-mm = <87>;

	grestb-gpios = <&foo_gpio 5 GPIO_ACTIVE_LOW>;

	backlight = <&bl>;

	port {

		nomadik_clcd_panel: endpoint {

			remote-endpoint = <&foo>;

		};

	};

};

# SPDX-License-Identifier: GPL-2.0

%YAML 1.2

---

$id: http://devicetree.org/schemas/display/panel/tpo,tpg110.yaml#

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

title: TPO TPG110 Panel

maintainers:

  - Linus Walleij <linus.walleij@linaro.org>

  - Thierry Reding <thierry.reding@gmail.com>

description: |+

  This panel driver is a component that acts as an intermediary

  between an RGB output and a variety of panels. The panel

  driver is strapped up in electronics to the desired resolution

  and other properties, and has a control interface over 3WIRE

  SPI. By talking to the TPG110 over SPI, the strapped properties

  can be discovered and the hardware is therefore mostly

  self-describing.

         +--------+

  SPI -> |  TPO   | -> physical display

  RGB -> | TPG110 |

         +--------+

  If some electrical strap or alternate resolution is desired,

  this can be set up by taking software control of the display

  over the SPI interface. The interface can also adjust

  for properties of the display such as gamma correction and

  certain electrical driving levels.

  The TPG110 does not know the physical dimensions of the panel

  connected, so this needs to be specified in the device tree.

  It requires a GPIO line for control of its reset line.

  The serial protocol has line names that resemble I2C but the

  protocol is not I2C but 3WIRE SPI.

allOf:

  - $ref: panel-common.yaml#

properties:

  compatible:

    oneOf:

      - items:

          - enum:

              - ste,nomadik-nhk15-display

          - const: tpo,tpg110

      - const: tpo,tpg110

  reg: true

  grestb-gpios:

    maxItems: 1

    description: panel reset GPIO

  spi-3wire: true

  spi-max-frequency:

    const: 3000000

required:

  - compatible

  - reg

  - grestb-gpios

  - width-mm

  - height-mm

  - spi-3wire

  - spi-max-frequency

  - port

examples:

  - |+

    spi {

      #address-cells = <1>;

      #size-cells = <0>;

      panel: display@0 {

        compatible = "tpo,tpg110";

        reg = <0>;

        spi-3wire;

        /* 320 ns min period ~= 3 MHz */

        spi-max-frequency = <3000000>;

        /* Width and height from data sheet */

        width-mm = <116>;

        height-mm = <87>;

        grestb-gpios = <&foo_gpio 5 1>;

        backlight = <&bl>;

        port {

          nomadik_clcd_panel: endpoint {

            remote-endpoint = <&foo>;

          };

        };

      };

    };

...

T:	git git://anongit.freedesktop.org/drm/drm-misc

S:	Maintained

F:	drivers/gpu/drm/panel/panel-tpo-tpg110.c

F:	Documentation/devicetree/bindings/display/panel/tpo,tpg110.txt

F:	Documentation/devicetree/bindings/display/panel/tpo,tpg110.yaml

DRM DRIVER FOR USB DISPLAYLINK VIDEO ADAPTERS

M:	Dave Airlie <airlied@redhat.com>