Commit 72820915 authored by Jonathan Cameron's avatar Jonathan Cameron
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dt-bindings:iio:adc:atmel, sama9260-adc: conversion to yaml from at91_adc.txt 



There are a few things we would do differently in an ADC binding if we
were starting from scratch but we are stuck with what we have (which
made sense back when this was written!)

We may be able to tighten up some elements of this binding in the future
by careful checking of what values properties can actually take.

Note the unusual sign off chain is representative of the path this patch
took.

Jonathan wrote the patch, which was then included in a series by
Alexandre and ultimately applied by Jonathan.

[Alexandre Belloni: add sama5d3, remove atmel,adc-res and atmel,adc-res-names]

Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Reviewed-by: default avatarLudovic Desroches <ludovic.desroches@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20201128222818.1910764-5-alexandre.belloni@bootlin.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent d1ad1041

Documentation/devicetree/bindings/iio/adc/at91_adc.txt

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* AT91's Analog to Digital Converter (ADC)



Required properties:

  - compatible: Should be "atmel,<chip>-adc"

    <chip> can be "at91sam9260", "at91sam9g45", "at91sam9x5" or "sama5d3"

  - reg: Should contain ADC registers location and length

  - interrupts: Should contain the IRQ line for the ADC

  - clock-names: tuple listing input clock names.

	Required elements: "adc_clk", "adc_op_clk".

  - clocks: phandles to input clocks.

  - atmel,adc-channels-used: Bitmask of the channels muxed and enabled for this

    device

  - atmel,adc-startup-time: Startup Time of the ADC in microseconds as

    defined in the datasheet

  - atmel,adc-vref: Reference voltage in millivolts for the conversions



Optional properties:

  - atmel,adc-use-external-triggers: Boolean to enable the external triggers

  - atmel,adc-use-res: String selecting the resolution, can be "lowres" or

		       "highres". If not specified, the highest resolution will

		       be used.

  - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion

  - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds

  - atmel,adc-ts-wires: Number of touchscreen wires. Should be 4 or 5. If this

                        value is set, then the adc driver will enable touchscreen

                        support.

    NOTE: when adc touchscreen is enabled, the adc hardware trigger will be

          disabled. Since touchscreen will occupy the trigger register.

  - atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It

                                     makes touch detection more precise.



Optional trigger Nodes:

  - Required properties:

    * trigger-name: Name of the trigger exposed to the user

    * trigger-value: Value to put in the Trigger register

      to activate this trigger

  - Optional properties:

    * trigger-external: Is the trigger an external trigger?



Examples:

adc0: adc@fffb0000 {

	#address-cells = <1>;

	#size-cells = <0>;

	compatible = "atmel,at91sam9260-adc";

	reg = <0xfffb0000 0x100>;

	interrupts = <20 IRQ_TYPE_LEVEL_HIGH 0>;

	clocks = <&adc_clk>, <&adc_op_clk>;

	clock-names = "adc_clk", "adc_op_clk";

	atmel,adc-channels-used = <0xff>;

	atmel,adc-startup-time = <40>;

	atmel,adc-use-external-triggers;

	atmel,adc-vref = <3300>;

	atmel,adc-res = <8 10>;

	atmel,adc-res-names = "lowres", "highres";

	atmel,adc-use-res = "lowres";



	trigger0 {

		trigger-name = "external-rising";

		trigger-value = <0x1>;

		trigger-external;

	};

	trigger1 {

		trigger-name = "external-falling";

		trigger-value = <0x2>;

		trigger-external;

	};



	trigger2 {

		trigger-name = "external-any";

		trigger-value = <0x3>;

		trigger-external;

	};



	trigger3 {

		trigger-name = "continuous";

		trigger-value = <0x6>;

	};

};

Documentation/devicetree/bindings/iio/adc/atmel,sama9260-adc.yaml

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

%YAML 1.2

---

$id: http://devicetree.org/schemas/iio/adc/atmel,sama9260-adc.yaml#

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



title: AT91 sama9260 and similar Analog to Digital Converter (ADC)



maintainers:

  - Alexandre Belloni <alexandre.belloni@bootlin.com>



properties:

  compatible:

    enum:

      - atmel,at91sam9260-adc

      - atmel,at91sam9rl-adc

      - atmel,at91sam9g45-adc

      - atmel,at91sam9x5-adc

      - atmel,at91sama5d3-adc



  reg:

    maxItems: 1



  interrupts:

    maxItems: 1



  clocks:

    minItems: 2

    maxItems: 2



  clock-names:

    items:

      - const: adc_clk

      - const: adc_op_clk



  atmel,adc-channels-used:

    $ref: /schemas/types.yaml#/definitions/uint32

    description: Bitmask of the channels muxed and enabled for this device



  atmel,adc-startup-time:

    $ref: /schemas/types.yaml#/definitions/uint32

    description:

      Startup Time of the ADC in microseconds as defined in the datasheet



  atmel,adc-vref:

    $ref: /schemas/types.yaml#/definitions/uint32

    description: Reference voltage in millivolts for the conversions



  atmel,adc-use-external-triggers:

    $ref: /schemas/types.yaml#/definitions/flag

    description: Enable the external triggers



  atmel,adc-use-res:

    $ref: /schemas/types.yaml#/definitions/string

    description:

      String corresponding to an identifier from atmel,adc-res-names property.

      If not specified, the highest resolution will be used.

    enum:

      - "lowres"

      - "highres"



  atmel,adc-sleep-mode:

    $ref: /schemas/types.yaml#/definitions/flag

    description: Enable sleep mode when no conversion



  atmel,adc-sample-hold-time:

    $ref: /schemas/types.yaml#/definitions/uint32

    description: Sample and Hold Time in microseconds



  atmel,adc-ts-wires:

    $ref: /schemas/types.yaml#/definitions/uint32

    description: |

      Number of touchscreen wires. Must be set to enable touchscreen.

      NOTE: when adc touchscreen is enabled, the adc hardware trigger will be

      disabled. Since touchscreen will occupy the trigger register.

    enum:

      - 4

      - 5



  atmel,adc-ts-pressure-threshold:

    $ref: /schemas/types.yaml#/definitions/uint32

    description:

      Pressure threshold for touchscreen.



  "#io-channel-cells":

    const: 1



additionalProperties: false



required:

  - compatible

  - reg

  - interrupts

  - clocks

  - clock-names

  - atmel,adc-channels-used

  - atmel,adc-startup-time

  - atmel,adc-vref



patternProperties:

  "^(trigger)[0-9]$":

    type: object

    description: Child node to describe a trigger exposed to the user.

    properties:

      trigger-name:

        $ref: /schemas/types.yaml#/definitions/string

        description: Identifying name.



      trigger-value:

        $ref: /schemas/types.yaml#/definitions/uint32

        description:

          Value to put in the Trigger register to activate this trigger



      trigger-external:

        $ref: /schemas/types.yaml#/definitions/flag

        description: This trigger is provided from an external pin.



    additionalProperties: false

    required:

      - trigger-name

      - trigger-value



examples:

  - |

    #include <dt-bindings/dma/at91.h>

    #include <dt-bindings/interrupt-controller/irq.h>

    soc {

        #address-cells = <1>;

        #size-cells = <1>;



        adc@fffb0000 {

            compatible = "atmel,at91sam9260-adc";

            reg = <0xfffb0000 0x100>;

            interrupts = <20 IRQ_TYPE_LEVEL_HIGH 0>;

            clocks = <&adc_clk>, <&adc_op_clk>;

            clock-names = "adc_clk", "adc_op_clk";

            atmel,adc-channels-used = <0xff>;

            atmel,adc-startup-time = <40>;

            atmel,adc-use-external-triggers;

            atmel,adc-vref = <3300>;

            atmel,adc-use-res = "lowres";



            trigger0 {

                trigger-name = "external-rising";

                trigger-value = <0x1>;

                trigger-external;

            };



            trigger1 {

                trigger-name = "external-falling";

                trigger-value = <0x2>;

                trigger-external;

            };



            trigger2 {

                trigger-name = "external-any";

                trigger-value = <0x3>;

                trigger-external;

            };



            trigger3 {

                trigger-name = "continuous";

                trigger-value = <0x6>;

            };

        };

    };

...