media: dt-bindings: cec-gpio: convert to DT schema

* HDMI CEC GPIO driver

The HDMI CEC GPIO module supports CEC implementations where the CEC line

is hooked up to a pull-up GPIO line and - optionally - the HPD line is

hooked up to another GPIO line.

Please note: the maximum voltage for the CEC line is 3.63V, for the HPD and

5V lines it is 5.3V. So you may need some sort of level conversion circuitry

when connecting them to a GPIO line.

Required properties:

  - compatible: value must be "cec-gpio".

  - cec-gpios: gpio that the CEC line is connected to. The line should be

    tagged as open drain.

If the CEC line is associated with an HDMI receiver/transmitter, then the

following property is also required:

  - hdmi-phandle - phandle to the HDMI controller, see also cec.txt.

If the CEC line is not associated with an HDMI receiver/transmitter, then

the following property is optional and can be used for debugging HPD changes:

  - hpd-gpios: gpio that the HPD line is connected to.

This property is optional and can be used for debugging changes on the 5V line:

  - v5-gpios: gpio that the 5V line is connected to.

Example for the Raspberry Pi 3 where the CEC line is connected to

pin 26 aka BCM7 aka CE1 on the GPIO pin header, the HPD line is

connected to pin 11 aka BCM17 and the 5V line is connected to pin

15 aka BCM22 (some level shifter is needed for the HPD and 5V lines!):

#include <dt-bindings/gpio/gpio.h>

cec-gpio {

	compatible = "cec-gpio";

	cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;

	hpd-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>;

	v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;

};

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

%YAML 1.2

---

$id: http://devicetree.org/schemas/media/cec/cec-gpio.yaml#

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

title: HDMI CEC GPIO

maintainers:

  - Hans Verkuil <hverkuil-cisco@xs4all.nl>

description: |

  The HDMI CEC GPIO module supports CEC implementations where the CEC line is

  hooked up to a pull-up GPIO line and - optionally - the HPD line is hooked up

  to another GPIO line.

  Please note:: the maximum voltage for the CEC line is 3.63V, for the HPD and

  5V lines it is 5.3V. So you may need some sort of level conversion

  circuitry when connecting them to a GPIO line.

properties:

  compatible:

    const: cec-gpio

  cec-gpios:

    maxItems: 1

    description:

      GPIO that the CEC line is connected to. The line should be tagged as open

      drain.

  hpd-gpios:

    maxItems: 1

    description:

      GPIO that the HPD line is connected to.  Used for debugging HPD changes

      when the CEC line is not associated with an HDMI receiver/transmitter.

  v5-gpios:

    maxItems: 1

    description:

      GPIO that the 5V line is connected to.  Used for debugging changes on the

      5V line.

required:

  - compatible

  - cec-gpios

allOf:

  - $ref: cec-common.yaml#

  - if:

      required:

        - hdmi-phandle

    then:

      properties:

        hpd-gpios: false

  - if:

      required:

        - hpd-gpios

    then:

      properties:

        hdmi-phandle: false

unevaluatedProperties: false

examples:

  - |

    #include <dt-bindings/gpio/gpio.h>

    cec {

        compatible = "cec-gpio";

        cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;

        hpd-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>;

        v5-gpios = <&gpio 22 GPIO_ACTIVE_HIGH>;

    };

S:	Supported

W:	http://linuxtv.org

T:	git git://linuxtv.org/media_tree.git

F:	Documentation/devicetree/bindings/media/cec-gpio.txt

F:	Documentation/devicetree/bindings/media/cec/cec-gpio.yaml

F:	drivers/media/cec/platform/cec-gpio/

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