iio: adc: Convert the QCOM SPMI ADC bindings to .yaml format

Qualcomm's SPMI PMIC ADC

- SPMI PMIC voltage ADC (VADC) provides interface to clients to read

  voltage. The VADC is a 15-bit sigma-delta ADC.

- SPMI PMIC5 voltage ADC (ADC) provides interface to clients to read

  voltage. The VADC is a 16-bit sigma-delta ADC.

VADC node:

- compatible:

    Usage: required

    Value type: <string>

    Definition: Should contain "qcom,spmi-vadc".

                Should contain "qcom,spmi-adc5" for PMIC5 ADC driver.

                Should contain "qcom,spmi-adc-rev2" for PMIC rev2 ADC driver.

                Should contain "qcom,pms405-adc" for PMS405 PMIC

- reg:

    Usage: required

    Value type: <prop-encoded-array>

    Definition: VADC base address in the SPMI PMIC register map.

- #address-cells:

    Usage: required

    Value type: <u32>

    Definition: Must be one. Child node 'reg' property should define ADC

            channel number.

- #size-cells:

    Usage: required

    Value type: <u32>

    Definition: Must be zero.

- #io-channel-cells:

    Usage: required

    Value type: <u32>

    Definition: Must be one. For details about IIO bindings see:

            Documentation/devicetree/bindings/iio/iio-bindings.txt

- interrupts:

    Usage: optional

    Value type: <prop-encoded-array>

    Definition: End of conversion interrupt.

Channel node properties:

- reg:

    Usage: required

    Value type: <u32>

    Definition: ADC channel number.

            See include/dt-bindings/iio/qcom,spmi-vadc.h

- label:

    Usage: required for "qcom,spmi-adc5" and "qcom,spmi-adc-rev2"

    Value type: <empty>

    Definition: ADC input of the platform as seen in the schematics.

            For thermistor inputs connected to generic AMUX or GPIO inputs

            these can vary across platform for the same pins. Hence select

            the platform schematics name for this channel.

- qcom,decimation:

    Usage: optional

    Value type: <u32>

    Definition: This parameter is used to decrease ADC sampling rate.

            Quicker measurements can be made by reducing decimation ratio.

            - For compatible property "qcom,spmi-vadc", valid values are

              512, 1024, 2048, 4096. If property is not found, default value

              of 512 will be used.

            - For compatible property "qcom,spmi-adc5", valid values are 250, 420

              and 840. If property is not found, default value of 840 is used.

            - For compatible property "qcom,spmi-adc-rev2", valid values are 256,

              512 and 1024. If property is not present, default value is 1024.

- qcom,pre-scaling:

    Usage: optional

    Value type: <u32 array>

    Definition: Used for scaling the channel input signal before the signal is

            fed to VADC. The configuration for this node is to know the

            pre-determined ratio and use it for post scaling. Select one from

            the following options.

            <1 1>, <1 3>, <1 4>, <1 6>, <1 20>, <1 8>, <10 81>, <1 10>

            If property is not found default value depending on chip will be used.

- qcom,ratiometric:

    Usage: optional

    Value type: <empty>

    Definition: Channel calibration type.

            - For compatible property "qcom,spmi-vadc", if this property is

              specified VADC will use the VDD reference (1.8V) and GND for

              channel calibration. If property is not found, channel will be

              calibrated with 0.625V and 1.25V reference channels, also

              known as absolute calibration.

            - For compatible property "qcom,spmi-adc5" and "qcom,spmi-adc-rev2",

              if this property is specified VADC will use the VDD reference

              (1.875V) and GND for channel calibration. If property is not found,

              channel will be calibrated with 0V and 1.25V reference channels,

              also known as absolute calibration.

- qcom,hw-settle-time:

    Usage: optional

    Value type: <u32>

    Definition: Time between AMUX getting configured and the ADC starting

            conversion. The 'hw_settle_time' is an index used from valid values

            and programmed in hardware to achieve the hardware settling delay.

            - For compatible property "qcom,spmi-vadc" and "qcom,spmi-adc-rev2",

              Delay = 100us * (hw_settle_time) for hw_settle_time < 11,

              and 2ms * (hw_settle_time - 10) otherwise.

              Valid values are: 0, 100, 200, 300, 400, 500, 600, 700, 800,

              900 us and 1, 2, 4, 6, 8, 10 ms.

              If property is not found, channel will use 0us.

            - For compatible property "qcom,spmi-adc5", delay = 15us for

              value 0, 100us * (value) for values < 11,

              and 2ms * (value - 10) otherwise.

              Valid values are: 15, 100, 200, 300, 400, 500, 600, 700, 800,

              900 us and 1, 2, 4, 6, 8, 10 ms

              Certain controller digital versions have valid values of

              15, 100, 200, 300, 400, 500, 600, 700, 1, 2, 4, 8, 16, 32, 64, 128 ms

              If property is not found, channel will use 15us.

- qcom,avg-samples:

    Usage: optional

    Value type: <u32>

    Definition: Number of samples to be used for measurement.

            Averaging provides the option to obtain a single measurement

            from the ADC that is an average of multiple samples. The value

            selected is 2^(value).

            - For compatible property "qcom,spmi-vadc", valid values

              are: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512

              If property is not found, 1 sample will be used.

            - For compatible property "qcom,spmi-adc5" and "qcom,spmi-adc-rev2",

              valid values are: 1, 2, 4, 8, 16

              If property is not found, 1 sample will be used.

NOTE:

For compatible property "qcom,spmi-vadc" following channels, also known as

reference point channels, are used for result calibration and their channel

configuration nodes should be defined:

VADC_REF_625MV and/or VADC_SPARE1(based on PMIC version) VADC_REF_1250MV,

VADC_GND_REF and VADC_VDD_VADC.

Example:

#include <dt-bindings/iio/qcom,spmi-vadc.h>

#include <linux/irq.h>

/* ... */

	/* VADC node */

	pmic_vadc: vadc@3100 {

		compatible = "qcom,spmi-vadc";

		reg = <0x3100>;

		interrupts = <0x0 0x31 0x0 IRQ_TYPE_EDGE_RISING>;

		#address-cells = <1>;

		#size-cells = <0>;

		#io-channel-cells = <1>;

		io-channel-ranges;

		/* Channel node */

		adc-chan@VADC_LR_MUX10_USB_ID {

			reg = <VADC_LR_MUX10_USB_ID>;

			qcom,decimation = <512>;

			qcom,ratiometric;

			qcom,hw-settle-time = <200>;

			qcom,avg-samples = <1>;

			qcom,pre-scaling = <1 3>;

		};

	};

	/* IIO client node */

	usb {

		io-channels = <&pmic_vadc VADC_LR_MUX10_USB_ID>;

		io-channel-names = "vadc";

	};

# SPDX-License-Identifier: GPL-2.0-only

%YAML 1.2

---

$id: http://devicetree.org/schemas/iio/adc/qcom,spmi-vadc.yaml#

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

title: Qualcomm's SPMI PMIC ADC

maintainers:

  - Andy Gross <agross@kernel.org>

  - Bjorn Andersson <bjorn.andersson@linaro.org>

description: |

  SPMI PMIC voltage ADC (VADC) provides interface to clients to read

  voltage. The VADC is a 15-bit sigma-delta ADC.

  SPMI PMIC5 voltage ADC (ADC) provides interface to clients to read

  voltage. The VADC is a 16-bit sigma-delta ADC.

properties:

  compatible:

    oneOf:

      - items:

          - const: qcom,pms405-adc

          - const: qcom,spmi-adc-rev2

      - items:

        - enum:

          - qcom,spmi-vadc

          - qcom,spmi-adc5

          - qcom,spmi-adc-rev2

  reg:

    description: VADC base address in the SPMI PMIC register map

    maxItems: 1

  '#address-cells':

    const: 1

  '#size-cells':

    const: 0

  '#io-channel-cells':

    const: 1

  interrupts:

    maxItems: 1

    description:

      End of conversion interrupt.

required:

  - compatible

  - reg

  - '#address-cells'

  - '#size-cells'

  - '#io-channel-cells'

patternProperties:

  "^.*@[0-9a-f]+$":

    type: object

    description: |

      Represents the external channels which are connected to the ADC.

      For compatible property "qcom,spmi-vadc" following channels, also known as

      reference point channels, are used for result calibration and their channel

      configuration nodes should be defined:

      VADC_REF_625MV and/or VADC_SPARE1(based on PMIC version) VADC_REF_1250MV,

      VADC_GND_REF and VADC_VDD_VADC.

    properties:

      reg:

        description: |

          ADC channel number.

          See include/dt-bindings/iio/qcom,spmi-vadc.h

      label:

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

        description: |

            ADC input of the platform as seen in the schematics.

            For thermistor inputs connected to generic AMUX or GPIO inputs

            these can vary across platform for the same pins. Hence select

            the platform schematics name for this channel.

      qcom,decimation:

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

        description: |

            This parameter is used to decrease ADC sampling rate.

            Quicker measurements can be made by reducing decimation ratio.

      qcom,pre-scaling:

        description: |

            Used for scaling the channel input signal before the signal is

            fed to VADC. The configuration for this node is to know the

            pre-determined ratio and use it for post scaling. It is a pair of

            integers, denoting the numerator and denominator of the fraction by which

            input signal is multiplied. For example, <1 3> indicates the signal is scaled

            down to 1/3 of its value before ADC measurement.

            If property is not found default value depending on chip will be used.

        allOf:

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

        oneOf:

          - items:

            - const: 1

            - enum: [ 1, 3, 4, 6, 20, 8, 10 ]

          - items:

            - const: 10

            - const: 81

      qcom,ratiometric:

        description: |

            Channel calibration type.

            - For compatible property "qcom,spmi-vadc", if this property is

              specified VADC will use the VDD reference (1.8V) and GND for

              channel calibration. If property is not found, channel will be

              calibrated with 0.625V and 1.25V reference channels, also

              known as absolute calibration.

            - For compatible property "qcom,spmi-adc5" and "qcom,spmi-adc-rev2",

              if this property is specified VADC will use the VDD reference (1.875V)

              and GND for channel calibration. If property is not found, channel

              will be calibrated with 0V and 1.25V reference channels, also known

              as absolute calibration.

        type: boolean

      qcom,hw-settle-time:

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

        description: |

            Time between AMUX getting configured and the ADC starting

            conversion. The 'hw_settle_time' is an index used from valid values

            and programmed in hardware to achieve the hardware settling delay.

      qcom,avg-samples:

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

        description: |

            Number of samples to be used for measurement.

            Averaging provides the option to obtain a single measurement

            from the ADC that is an average of multiple samples. The value

            selected is 2^(value).

    required:

      - reg

allOf:

  - if:

      properties:

        compatible:

          contains:

            const: qcom,spmi-vadc

    then:

      patternProperties:

        "^.*@[0-9a-f]+$":

          properties:

            qcom,decimation:

              enum: [ 512, 1024, 2048, 4096 ]

              default: 512

            qcom,hw-settle-time:

              enum: [ 0, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1, 2,

                      4, 6, 8, 10 ]

              default: 0

            qcom,avg-samples:

              enum: [ 1, 2, 4, 8, 16, 32, 64, 128, 256, 512 ]

              default: 1

  - if:

      properties:

        compatible:

          contains:

            const: qcom,spmi-adc-rev2

    then:

      patternProperties:

        "^.*@[0-9a-f]+$":

          properties:

            qcom,decimation:

              enum: [ 256, 512, 1024 ]

              default: 1024

            qcom,hw-settle-time:

              enum: [ 0, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1, 2,

                      4, 6, 8, 10 ]

              default: 0

            qcom,avg-samples:

              enum: [ 1, 2, 4, 8, 16 ]

              default: 1

  - if:

      properties:

        compatible:

          contains:

            const: qcom,spmi-adc5

    then:

      patternProperties:

        "^.*@[0-9a-f]+$":

          properties:

            qcom,decimation:

              enum: [ 250, 420, 840 ]

              default: 840

            qcom,hw-settle-time:

              enum: [ 15, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1, 2,

                      4, 6, 8, 10, 16, 32, 64, 128 ]

              default: 15

            qcom,avg-samples:

              enum: [ 1, 2, 4, 8, 16 ]

              default: 1

examples:

  - |

    spmi_bus {

      #address-cells = <1>;

      #size-cells = <0>;

      /* VADC node */

      pmic_vadc: adc@3100 {

        compatible = "qcom,spmi-vadc";

        reg = <0x3100>;

        interrupts = <0x0 0x31 0x0 0x1>;

        #address-cells = <1>;

        #size-cells = <0>;

        #io-channel-cells = <1>;

        io-channel-ranges;

        /* Channel node */

        adc-chan@39 {

          reg = <0x39>;

          qcom,decimation = <512>;

          qcom,ratiometric;

          qcom,hw-settle-time = <200>;

          qcom,avg-samples = <1>;

          qcom,pre-scaling = <1 3>;

        };

        adc-chan@9 {

          reg = <0x9>;

        };

        adc-chan@a {

          reg = <0xa>;

        };

        adc-chan@e {

          reg = <0xe>;

        };

        adc-chan@f {

          reg = <0xf>;

        };

      };

    };