[v2] dt-bindings: iio: adc: stm32-adc: convert bindings to json-schema

Commit Message

Fabrice Gasnier Dec. 6, 2019, 4:17 p.m. UTC

Convert the STM32 ADC binding to DT schema format using json-schema

Signed-off-by: Fabrice Gasnier <[e-mail]>
---
Note: this applies on top of IIO tree currently (iio-for-5.5c).

Changes in V2:
- Take almost all of Rob suggestions (removed reg generic description,
  added minItems, maxItems, st,max-clk-rate-hz range, drop some pipes,
  simplify clock-names, remove unneeded allOfs)
- For now, keep all in one file despite there are lots of if/thens in the
  bindings
---
 .../devicetree/bindings/iio/adc/st,stm32-adc.txt   | 149 -------
 .../devicetree/bindings/iio/adc/st,stm32-adc.yaml  | 454 +++++++++++++++++++++
 2 files changed, 454 insertions(+), 149 deletions(-)
 delete mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
 create mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml

Comments

Rob Herring Dec. 17, 2019, 11:43 p.m. UTC | #1

On Fri, Dec 06, 2019 at 05:17:08PM +0100, Fabrice Gasnier wrote:
> Convert the STM32 ADC binding to DT schema format using json-schema
> 
> Signed-off-by: Fabrice Gasnier <[e-mail]>
> ---
> Note: this applies on top of IIO tree currently (iio-for-5.5c).
> 
> Changes in V2:
> - Take almost all of Rob suggestions (removed reg generic description,
>   added minItems, maxItems, st,max-clk-rate-hz range, drop some pipes,
>   simplify clock-names, remove unneeded allOfs)
> - For now, keep all in one file despite there are lots of if/thens in the
>   bindings
> ---
>  .../devicetree/bindings/iio/adc/st,stm32-adc.txt   | 149 -------
>  .../devicetree/bindings/iio/adc/st,stm32-adc.yaml  | 454 +++++++++++++++++++++
>  2 files changed, 454 insertions(+), 149 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml


> diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
> new file mode 100644
> index 00000000..60a0212
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
> @@ -0,0 +1,454 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/bindings/iio/adc/st,stm32-adc.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: STMicroelectronics STM32 ADC bindings
> +
> +description: |
> +  STM32 ADC is a successive approximation analog-to-digital converter.
> +  It has several multiplexed input channels. Conversions can be performed
> +  in single, continuous, scan or discontinuous mode. Result of the ADC is
> +  stored in a left-aligned or right-aligned 32-bit data register.
> +  Conversions can be launched in software or using hardware triggers.
> +
> +  The analog watchdog feature allows the application to detect if the input
> +  voltage goes beyond the user-defined, higher or lower thresholds.
> +
> +  Each STM32 ADC block can have up to 3 ADC instances.
> +
> +maintainers:
> +  - Fabrice Gasnier <[e-mail]>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - st,stm32f4-adc-core
> +      - st,stm32h7-adc-core
> +      - st,stm32mp1-adc-core
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    description: |
> +      One or more interrupts for ADC block, depending on part used:
> +        - stm32f4 and stm32h7 share a common ADC interrupt line.
> +        - stm32mp1 has two separate interrupt lines, one for each ADC within
> +          ADC block.
> +    minItems: 1
> +    maxItems: 2
> +
> +  clocks:
> +    description: |
> +      Core can use up to two clocks, depending on part used:
> +        - "adc" clock: for the analog circuitry, common to all ADCs.
> +          It's required on stm32f4.
> +          It's optional on stm32h7 and stm32mp1.
> +        - "bus" clock: for registers access, common to all ADCs.
> +          It's not present on stm32f4.
> +          It's required on stm32h7 and stm32mp1.
> +
> +  clock-names: true
> +
> +  st,max-clk-rate-hz:
> +    description:
> +      Allow to specify desired max clock rate used by analog circuitry.
> +
> +  vdda-supply:
> +    description: Phandle to the vdda input analog voltage.
> +
> +  vref-supply:
> +    description: Phandle to the vref input analog reference voltage.
> +
> +  booster-supply:
> +    description:
> +      Phandle to the embedded booster regulator that can be used to supply ADC
> +      analog input switches on stm32h7 and stm32mp1.
> +
> +  vdd-supply:
> +    description:
> +      Phandle to the vdd input voltage. It can be used to supply ADC analog
> +      input switches on stm32mp1.
> +
> +  st,syscfg:
> +    description:
> +      Phandle to system configuration controller. It can be used to control the
> +      analog circuitry on stm32mp1.
> +    allOf:
> +      - $ref: "/schemas/types.yaml#/definitions/phandle-array"
> +
> +  interrupt-controller: true
> +
> +  '#interrupt-cells':
> +    const: 1
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: st,stm32f4-adc-core
> +
> +    then:
> +      properties:
> +        clocks:
> +          maxItems: 1
> +
> +        clock-names:
> +          const: adc
> +
> +        interrupts:
> +          items:
> +            - description: interrupt line common for all ADCs
> +
> +        st,max-clk-rate-hz:
> +          minimum: 600000
> +          maximum: 36000000
> +          default: 36000000
> +
> +        booster-supply: false
> +
> +        vdd-supply: false
> +
> +        st,syscfg: false
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: st,stm32h7-adc-core
> +
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 1
> +          maxItems: 2
> +
> +        clock-names:
> +          items:
> +            - const: bus
> +            - const: adc
> +          minItems: 1
> +          maxItems: 2
> +
> +        interrupts:
> +          items:
> +            - description: interrupt line common for all ADCs
> +
> +        st,max-clk-rate-hz:
> +          minimum: 120000
> +          maximum: 36000000
> +          default: 36000000
> +
> +        vdd-supply: false
> +
> +        st,syscfg: false
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: st,stm32mp1-adc-core
> +
> +    then:
> +      properties:
> +        clocks:
> +          minItems: 1
> +          maxItems: 2
> +
> +        clock-names:
> +          items:
> +            - const: bus
> +            - const: adc
> +          minItems: 1
> +          maxItems: 2
> +
> +        interrupts:
> +          items:
> +            - description: interrupt line for ADC1
> +            - description: interrupt line for ADC2
> +
> +        st,max-clk-rate-hz:
> +          minimum: 120000
> +          maximum: 36000000
> +          default: 36000000
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - vdda-supply
> +  - vref-supply
> +  - interrupt-controller
> +  - '#interrupt-cells'
> +  - '#address-cells'
> +  - '#size-cells'
> +
> +patternProperties:
> +  "^adc@[0-9]+$":
> +    type: object
> +    description:
> +      An ADC block node should contain at least one subnode, representing an
> +      ADC instance available on the machine.
> +
> +    properties:
> +      compatible:
> +        enum:
> +          - st,stm32f4-adc
> +          - st,stm32h7-adc
> +          - st,stm32mp1-adc
> +
> +      reg:
> +        description: |
> +          Offset of ADC instance in ADC block. Valid values are:
> +            - 0x0:   ADC1
> +            - 0x100: ADC2
> +            - 0x200: ADC3 (stm32f4 only)
> +        maxItems: 1
> +
> +      '#io-channel-cells':
> +        const: 1
> +
> +      interrupts:
> +        description: |
> +          IRQ Line for the ADC instance. Valid values are:
> +            - 0 for adc@0
> +            - 1 for adc@100
> +            - 2 for adc@200 (stm32f4 only)
> +        maxItems: 1
> +
> +      clocks:
> +        description:
> +          Input clock private to this ADC instance. It's required only on
> +          stm32f4, that has per instance clock input for registers access.
> +        maxItems: 1
> +
> +      dmas:
> +        description: RX DMA Channel
> +        maxItems: 1
> +
> +      dma-names:
> +        const: rx
> +
> +      assigned-resolution-bits:
> +        description: |
> +          Resolution (bits) to use for conversions:
> +            - can be 6, 8, 10 or 12 on stm32f4
> +            - can be 8, 10, 12, 14 or 16 on stm32h7 and stm32mp1
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +
> +      st,adc-channels:
> +        description: |
> +          List of single-ended channels muxed for this ADC. It can have up to:
> +            - 16 channels, numbered from 0 to 15 (for in0..in15) on stm32f4
> +            - 20 channels, numbered from 0 to 19 (for in0..in19) on stm32h7 and
> +              stm32mp1.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32-array
> +
> +      st,adc-diff-channels:
> +        description: |
> +          List of differential channels muxed for this ADC. Some channels can
> +          be configured as differential instead of single-ended on stm32h7 and
> +          on stm32mp1. Positive and negative inputs pairs are listed:
> +          <vinp vinn>, <vinp vinn>,... vinp and vinn are numbered from 0 to 19.
> +
> +          Note: At least one of "st,adc-channels" or "st,adc-diff-channels" is
> +          required. Both properties can be used together. Some channels can be
> +          used as single-ended and some other ones as differential (mixed). But
> +          channels can't be configured both as single-ended and differential.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32-matrix
> +          - items:
> +              items:
> +                - description: |
> +                    "vinp" indicates positive input number
> +                  minimum: 0
> +                  maximum: 19
> +                - description: |
> +                    "vinn" indicates negative input number
> +                  minimum: 0
> +                  maximum: 19
> +
> +      st,min-sample-time-nsecs:
> +        description:
> +          Minimum sampling time in nanoseconds. Depending on hardware (board)
> +          e.g. high/low analog input source impedance, fine tune of ADC
> +          sampling time may be recommended. This can be either one value or an
> +          array that matches "st,adc-channels" and/or "st,adc-diff-channels"
> +          list, to set sample time resp. for all channels, or independently for
> +          each channel.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32-array
> +
> +    allOf:
> +      - if:
> +          properties:
> +            compatible:
> +              contains:
> +                const: st,stm32f4-adc
> +
> +        then:
> +          properties:
> +            reg:
> +              enum:
> +                - 0x0
> +                - 0x100
> +                - 0x200
> +
> +            interrupts:
> +              minimum: 0
> +              maximum: 2
> +
> +            assigned-resolution-bits:
> +              enum: [6, 8, 10, 12]
> +              default: 12
> +
> +            st,adc-channels:
> +              minItems: 1
> +              maxItems: 16
> +              minimum: 0
> +              maximum: 15

You are mixing array and scalar constraints here. You need:

minItems: 1
maxItems:16
items:
  minimum: 0
  maximum: 15

Update dtschema. It will now catch this. There's a few others too.


> +
> +            st,adc-diff-channels: false
> +
> +            st,min-sample-time-nsecs:
> +              minItems: 1
> +              maxItems: 16
> +              minimum: 80
> +
> +          required:
> +            - clocks
> +
> +      - if:
> +          properties:
> +            compatible:
> +              contains:
> +                enum:
> +                  - st,stm32h7-adc
> +                  - st,stm32mp1-adc
> +
> +        then:
> +          properties:
> +            reg:
> +              enum:
> +                - 0x0
> +                - 0x100
> +
> +            interrupts:
> +              minimum: 0
> +              maximum: 1
> +
> +            assigned-resolution-bits:
> +              enum: [8, 10, 12, 14, 16]
> +              default: 16
> +
> +            st,adc-channels:
> +              minItems: 1
> +              maxItems: 20
> +              minimum: 0
> +              maximum: 19
> +
> +            st,min-sample-time-nsecs:
> +              minItems: 1
> +              maxItems: 20
> +              minimum: 40
> +
> +    additionalProperties: false
> +
> +    anyOf:
> +      - required:
> +          - st,adc-channels
> +      - required:
> +          - st,adc-diff-channels
> +
> +    required:
> +      - compatible
> +      - reg
> +      - interrupts
> +      - '#io-channel-cells'
> +
> +examples:
> +  - |
> +    // Example 1: with stm32f429
> +      adc123: adc@40012000 {
> +        compatible = "st,stm32f4-adc-core";
> +        reg = <0x40012000 0x400>;
> +        interrupts = <18>;
> +        clocks = <&rcc 0 168>;
> +        clock-names = "adc";
> +        st,max-clk-rate-hz = <36000000>;
> +        vdda-supply = <&vdda>;
> +        vref-supply = <&vref>;
> +        interrupt-controller;
> +        #interrupt-cells = <1>;
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        adc@0 {
> +          compatible = "st,stm32f4-adc";
> +          #io-channel-cells = <1>;
> +          reg = <0x0>;
> +          clocks = <&rcc 0 168>;
> +          interrupt-parent = <&adc123>;
> +          interrupts = <0>;
> +          st,adc-channels = <8>;
> +          dmas = <&dma2 0 0 0x400 0x0>;
> +          dma-names = "rx";
> +          assigned-resolution-bits = <8>;
> +        };
> +        // ...
> +        // other adc child nodes follow...
> +      };
> +
> +  - |
> +    // Example 2: with stm32mp157c to setup ADC1 with:
> +    // - channel 1 as single-ended
> +    // - channels 2 & 3 as differential (with resp. 6 & 7 negative inputs)
> +      #include <dt-bindings/interrupt-controller/arm-gic.h>
> +      #include <dt-bindings/clock/stm32mp1-clks.h>
> +      adc12: adc@48003000 {
> +        compatible = "st,stm32mp1-adc-core";
> +        reg = <0x48003000 0x400>;
> +        interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>,
> +                     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>;
> +        clocks = <&rcc ADC12>, <&rcc ADC12_K>;
> +        clock-names = "bus", "adc";
> +        booster-supply = <&booster>;
> +        vdd-supply = <&vdd>;
> +        vdda-supply = <&vdda>;
> +        vref-supply = <&vref>;
> +        st,syscfg = <&syscfg>;
> +        interrupt-controller;
> +        #interrupt-cells = <1>;
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +        adc@0 {
> +          compatible = "st,stm32mp1-adc";
> +          #io-channel-cells = <1>;
> +          reg = <0x0>;
> +          interrupt-parent = <&adc12>;
> +          interrupts = <0>;
> +          st,adc-channels = <1>;
> +          st,adc-diff-channels = <2 6>, <3 7>;
> +          st,min-sample-time-nsecs = <5000>;
> +          dmas = <&dmamux1 9 0x400 0x05>;
> +          dma-names = "rx";
> +        };
> +        // ...
> +        // other adc child node follow...
> +      };
> +
> +...
> -- 
> 2.7.4
>

Fabrice Gasnier Jan. 14, 2020, 4:01 p.m. UTC | #2

On 12/18/19 12:43 AM, Rob Herring wrote:
> On Fri, Dec 06, 2019 at 05:17:08PM +0100, Fabrice Gasnier wrote:
>> Convert the STM32 ADC binding to DT schema format using json-schema
>>
>> Signed-off-by: Fabrice Gasnier <[e-mail]>
>> ---
>> Note: this applies on top of IIO tree currently (iio-for-5.5c).
>>
>> Changes in V2:
>> - Take almost all of Rob suggestions (removed reg generic description,
>>   added minItems, maxItems, st,max-clk-rate-hz range, drop some pipes,
>>   simplify clock-names, remove unneeded allOfs)
>> - For now, keep all in one file despite there are lots of if/thens in the
>>   bindings
>> ---
>>  .../devicetree/bindings/iio/adc/st,stm32-adc.txt   | 149 -------
>>  .../devicetree/bindings/iio/adc/st,stm32-adc.yaml  | 454 +++++++++++++++++++++
>>  2 files changed, 454 insertions(+), 149 deletions(-)
>>  delete mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
>>  create mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
> 
> 


[snip]

>> +
>> +      st,adc-channels:
>> +        description: |
>> +          List of single-ended channels muxed for this ADC. It can have up to:
>> +            - 16 channels, numbered from 0 to 15 (for in0..in15) on stm32f4
>> +            - 20 channels, numbered from 0 to 19 (for in0..in19) on stm32h7 and
>> +              stm32mp1.
>> +        allOf:
>> +          - $ref: /schemas/types.yaml#/definitions/uint32-array
>> +

[snip]

>> +
>> +    allOf:
>> +      - if:
>> +          properties:
>> +            compatible:
>> +              contains:
>> +                const: st,stm32f4-adc
>> +
>> +        then:
>> +          properties:
>> +            reg:
>> +              enum:
>> +                - 0x0
>> +                - 0x100
>> +                - 0x200
>> +
>> +            interrupts:
>> +              minimum: 0
>> +              maximum: 2
>> +
>> +            assigned-resolution-bits:
>> +              enum: [6, 8, 10, 12]
>> +              default: 12
>> +
>> +            st,adc-channels:
>> +              minItems: 1
>> +              maxItems: 16
>> +              minimum: 0
>> +              maximum: 15
> 
> You are mixing array and scalar constraints here. You need:
> 
> minItems: 1
> maxItems:16
> items:
>   minimum: 0
>   maximum: 15
> 
> Update dtschema. It will now catch this. There's a few others too.

Hi Rob,

Sorry for the late reply. I updated dtschema. Now it catches it.

I've tried your suggestion, but when I test it, I don't get any error on
maxItems.

In the example: "st,adc-channels = <0>, <1>, ... more than 16 items;"

Is it possible I face some other issue with dtschema ?

I tried another way below... Not sure that's correct. But it catches
errors on maxItems:

            st,adc-channels:
              allOf:
                - minItems: 1
                  maxItems: 16
              items:
                minimum: 0
                maximum: 15

Error message is ... "is too long" with bad example above.

Please advise,
Regards,
Fabrice

> 
> 
>> +
>> +            st,adc-diff-channels: false
>> +
>> +            st,min-sample-time-nsecs:
>> +              minItems: 1
>> +              maxItems: 16
>> +              minimum: 80
>> +
>> +          required:
>> +            - clocks
>> +
>> +      - if:
>> +          properties:
>> +            compatible:
>> +              contains:
>> +                enum:
>> +                  - st,stm32h7-adc
>> +                  - st,stm32mp1-adc
>> +
>> +        then:
>> +          properties:
>> +            reg:
>> +              enum:
>> +                - 0x0
>> +                - 0x100
>> +
>> +            interrupts:
>> +              minimum: 0
>> +              maximum: 1
>> +
>> +            assigned-resolution-bits:
>> +              enum: [8, 10, 12, 14, 16]
>> +              default: 16
>> +
>> +            st,adc-channels:
>> +              minItems: 1
>> +              maxItems: 20
>> +              minimum: 0
>> +              maximum: 19
>> +
>> +            st,min-sample-time-nsecs:
>> +              minItems: 1
>> +              maxItems: 20
>> +              minimum: 40
>> +
>> +    additionalProperties: false
>> +
>> +    anyOf:
>> +      - required:
>> +          - st,adc-channels
>> +      - required:
>> +          - st,adc-diff-channels
>> +
>> +    required:
>> +      - compatible
>> +      - reg
>> +      - interrupts
>> +      - '#io-channel-cells'
>> +
>> +examples:
>> +  - |
>> +    // Example 1: with stm32f429
>> +      adc123: adc@40012000 {
>> +        compatible = "st,stm32f4-adc-core";
>> +        reg = <0x40012000 0x400>;
>> +        interrupts = <18>;
>> +        clocks = <&rcc 0 168>;
>> +        clock-names = "adc";
>> +        st,max-clk-rate-hz = <36000000>;
>> +        vdda-supply = <&vdda>;
>> +        vref-supply = <&vref>;
>> +        interrupt-controller;
>> +        #interrupt-cells = <1>;
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +        adc@0 {
>> +          compatible = "st,stm32f4-adc";
>> +          #io-channel-cells = <1>;
>> +          reg = <0x0>;
>> +          clocks = <&rcc 0 168>;
>> +          interrupt-parent = <&adc123>;
>> +          interrupts = <0>;
>> +          st,adc-channels = <8>;
>> +          dmas = <&dma2 0 0 0x400 0x0>;
>> +          dma-names = "rx";
>> +          assigned-resolution-bits = <8>;
>> +        };
>> +        // ...
>> +        // other adc child nodes follow...
>> +      };
>> +
>> +  - |
>> +    // Example 2: with stm32mp157c to setup ADC1 with:
>> +    // - channel 1 as single-ended
>> +    // - channels 2 & 3 as differential (with resp. 6 & 7 negative inputs)
>> +      #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +      #include <dt-bindings/clock/stm32mp1-clks.h>
>> +      adc12: adc@48003000 {
>> +        compatible = "st,stm32mp1-adc-core";
>> +        reg = <0x48003000 0x400>;
>> +        interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>,
>> +                     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>;
>> +        clocks = <&rcc ADC12>, <&rcc ADC12_K>;
>> +        clock-names = "bus", "adc";
>> +        booster-supply = <&booster>;
>> +        vdd-supply = <&vdd>;
>> +        vdda-supply = <&vdda>;
>> +        vref-supply = <&vref>;
>> +        st,syscfg = <&syscfg>;
>> +        interrupt-controller;
>> +        #interrupt-cells = <1>;
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +        adc@0 {
>> +          compatible = "st,stm32mp1-adc";
>> +          #io-channel-cells = <1>;
>> +          reg = <0x0>;
>> +          interrupt-parent = <&adc12>;
>> +          interrupts = <0>;
>> +          st,adc-channels = <1>;
>> +          st,adc-diff-channels = <2 6>, <3 7>;
>> +          st,min-sample-time-nsecs = <5000>;
>> +          dmas = <&dmamux1 9 0x400 0x05>;
>> +          dma-names = "rx";
>> +        };
>> +        // ...
>> +        // other adc child node follow...
>> +      };
>> +
>> +...
>> -- 
>> 2.7.4
>>

Rob Herring Jan. 14, 2020, 7:20 p.m. UTC | #3

On Tue, Jan 14, 2020 at 10:02 AM Fabrice Gasnier <[e-mail]> wrote:
>
> On 12/18/19 12:43 AM, Rob Herring wrote:
> > On Fri, Dec 06, 2019 at 05:17:08PM +0100, Fabrice Gasnier wrote:
> >> Convert the STM32 ADC binding to DT schema format using json-schema
> >>
> >> Signed-off-by: Fabrice Gasnier <[e-mail]>
> >> ---
> >> Note: this applies on top of IIO tree currently (iio-for-5.5c).
> >>
> >> Changes in V2:
> >> - Take almost all of Rob suggestions (removed reg generic description,
> >>   added minItems, maxItems, st,max-clk-rate-hz range, drop some pipes,
> >>   simplify clock-names, remove unneeded allOfs)
> >> - For now, keep all in one file despite there are lots of if/thens in the
> >>   bindings
> >> ---
> >>  .../devicetree/bindings/iio/adc/st,stm32-adc.txt   | 149 -------
> >>  .../devicetree/bindings/iio/adc/st,stm32-adc.yaml  | 454 +++++++++++++++++++++
> >>  2 files changed, 454 insertions(+), 149 deletions(-)
> >>  delete mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
> >>  create mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
> >
> >
>
>
> [snip]
>
> >> +
> >> +      st,adc-channels:
> >> +        description: |
> >> +          List of single-ended channels muxed for this ADC. It can have up to:
> >> +            - 16 channels, numbered from 0 to 15 (for in0..in15) on stm32f4
> >> +            - 20 channels, numbered from 0 to 19 (for in0..in19) on stm32h7 and
> >> +              stm32mp1.
> >> +        allOf:
> >> +          - $ref: /schemas/types.yaml#/definitions/uint32-array
> >> +
>
> [snip]
>
> >> +
> >> +    allOf:
> >> +      - if:
> >> +          properties:
> >> +            compatible:
> >> +              contains:
> >> +                const: st,stm32f4-adc
> >> +
> >> +        then:
> >> +          properties:
> >> +            reg:
> >> +              enum:
> >> +                - 0x0
> >> +                - 0x100
> >> +                - 0x200
> >> +
> >> +            interrupts:
> >> +              minimum: 0
> >> +              maximum: 2
> >> +
> >> +            assigned-resolution-bits:
> >> +              enum: [6, 8, 10, 12]
> >> +              default: 12
> >> +
> >> +            st,adc-channels:
> >> +              minItems: 1
> >> +              maxItems: 16
> >> +              minimum: 0
> >> +              maximum: 15
> >
> > You are mixing array and scalar constraints here. You need:
> >
> > minItems: 1
> > maxItems:16
> > items:
> >   minimum: 0
> >   maximum: 15
> >
> > Update dtschema. It will now catch this. There's a few others too.
>
> Hi Rob,
>
> Sorry for the late reply. I updated dtschema. Now it catches it.
>
> I've tried your suggestion, but when I test it, I don't get any error on
> maxItems.
>
> In the example: "st,adc-channels = <0>, <1>, ... more than 16 items;"
>
> Is it possible I face some other issue with dtschema ?

The problem is how "<0>, <1>" vs. "<0 1>" gets encoded. While those
are the same in the dtb, in yaml we have "[[0], [1]]" vs. "[[0, 1]]".
Making the brackets significant is helpful for some things like
phandle+args and 'reg' where we have a matrix of values, but for
arrays it just gets in the way. I think as I suggested is the right
form for the binding schema, and we need to either decide what's the
correct way for brackets or improve the tool to accept both ways.

Rob

Fabrice Gasnier Jan. 15, 2020, 1:34 p.m. UTC | #4

On 1/14/20 8:20 PM, Rob Herring wrote:
> On Tue, Jan 14, 2020 at 10:02 AM Fabrice Gasnier <[e-mail]> wrote:
>>
>> On 12/18/19 12:43 AM, Rob Herring wrote:
>>> On Fri, Dec 06, 2019 at 05:17:08PM +0100, Fabrice Gasnier wrote:
>>>> Convert the STM32 ADC binding to DT schema format using json-schema
>>>>
>>>> Signed-off-by: Fabrice Gasnier <[e-mail]>
>>>> ---
>>>> Note: this applies on top of IIO tree currently (iio-for-5.5c).
>>>>
>>>> Changes in V2:
>>>> - Take almost all of Rob suggestions (removed reg generic description,
>>>>   added minItems, maxItems, st,max-clk-rate-hz range, drop some pipes,
>>>>   simplify clock-names, remove unneeded allOfs)
>>>> - For now, keep all in one file despite there are lots of if/thens in the
>>>>   bindings
>>>> ---
>>>>  .../devicetree/bindings/iio/adc/st,stm32-adc.txt   | 149 -------
>>>>  .../devicetree/bindings/iio/adc/st,stm32-adc.yaml  | 454 +++++++++++++++++++++
>>>>  2 files changed, 454 insertions(+), 149 deletions(-)
>>>>  delete mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
>>>>  create mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
>>>
>>>
>>
>>
>> [snip]
>>
>>>> +
>>>> +      st,adc-channels:
>>>> +        description: |
>>>> +          List of single-ended channels muxed for this ADC. It can have up to:
>>>> +            - 16 channels, numbered from 0 to 15 (for in0..in15) on stm32f4
>>>> +            - 20 channels, numbered from 0 to 19 (for in0..in19) on stm32h7 and
>>>> +              stm32mp1.
>>>> +        allOf:
>>>> +          - $ref: /schemas/types.yaml#/definitions/uint32-array
>>>> +
>>
>> [snip]
>>
>>>> +
>>>> +    allOf:
>>>> +      - if:
>>>> +          properties:
>>>> +            compatible:
>>>> +              contains:
>>>> +                const: st,stm32f4-adc
>>>> +
>>>> +        then:
>>>> +          properties:
>>>> +            reg:
>>>> +              enum:
>>>> +                - 0x0
>>>> +                - 0x100
>>>> +                - 0x200
>>>> +
>>>> +            interrupts:
>>>> +              minimum: 0
>>>> +              maximum: 2
>>>> +
>>>> +            assigned-resolution-bits:
>>>> +              enum: [6, 8, 10, 12]
>>>> +              default: 12
>>>> +
>>>> +            st,adc-channels:
>>>> +              minItems: 1
>>>> +              maxItems: 16
>>>> +              minimum: 0
>>>> +              maximum: 15
>>>
>>> You are mixing array and scalar constraints here. You need:
>>>
>>> minItems: 1
>>> maxItems:16
>>> items:
>>>   minimum: 0
>>>   maximum: 15
>>>
>>> Update dtschema. It will now catch this. There's a few others too.
>>
>> Hi Rob,
>>
>> Sorry for the late reply. I updated dtschema. Now it catches it.
>>
>> I've tried your suggestion, but when I test it, I don't get any error on
>> maxItems.
>>
>> In the example: "st,adc-channels = <0>, <1>, ... more than 16 items;"
>>
>> Is it possible I face some other issue with dtschema ?
> 
> The problem is how "<0>, <1>" vs. "<0 1>" gets encoded. While those
> are the same in the dtb, in yaml we have "[[0], [1]]" vs. "[[0, 1]]".
> Making the brackets significant is helpful for some things like
> phandle+args and 'reg' where we have a matrix of values, but for
> arrays it just gets in the way. I think as I suggested is the right
> form for the binding schema, and we need to either decide what's the
> correct way for brackets or improve the tool to accept both ways.

Hi Rob,

Thanks for the quick answer and clarification.

I'll adopt the way you suggest in V3 (the dts files already use <0 1...>
syntax). I'll also update the example in the bindings to use it, to
point the right form.

Thanks,
Fabrice

> 
> Rob
>

Patch

diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
deleted file mode 100644
index 8de9331..00000000
--- a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
+++ /dev/null
@@ -1,149 +0,0 @@ 
-STMicroelectronics STM32 ADC device driver
-
-STM32 ADC is a successive approximation analog-to-digital converter.
-It has several multiplexed input channels. Conversions can be performed
-in single, continuous, scan or discontinuous mode. Result of the ADC is
-stored in a left-aligned or right-aligned 32-bit data register.
-Conversions can be launched in software or using hardware triggers.
-
-The analog watchdog feature allows the application to detect if the input
-voltage goes beyond the user-defined, higher or lower thresholds.
-
-Each STM32 ADC block can have up to 3 ADC instances.
-
-Each instance supports two contexts to manage conversions, each one has its
-own configurable sequence and trigger:
-- regular conversion can be done in sequence, running in background
-- injected conversions have higher priority, and so have the ability to
-  interrupt regular conversion sequence (either triggered in SW or HW).
-  Regular sequence is resumed, in case it has been interrupted.
-
-Contents of a stm32 adc root node:
------------------------------------
-Required properties:
-- compatible: Should be one of:
-  "st,stm32f4-adc-core"
-  "st,stm32h7-adc-core"
-  "st,stm32mp1-adc-core"
-- reg: Offset and length of the ADC block register set.
-- interrupts: One or more interrupts for ADC block. Some parts like stm32f4
-  and stm32h7 share a common ADC interrupt line. stm32mp1 has two separate
-  interrupt lines, one for each ADC within ADC block.
-- clocks: Core can use up to two clocks, depending on part used:
-  - "adc" clock: for the analog circuitry, common to all ADCs.
-    It's required on stm32f4.
-    It's optional on stm32h7.
-  - "bus" clock: for registers access, common to all ADCs.
-    It's not present on stm32f4.
-    It's required on stm32h7.
-- clock-names: Must be "adc" and/or "bus" depending on part used.
-- interrupt-controller: Identifies the controller node as interrupt-parent
-- vdda-supply: Phandle to the vdda input analog voltage.
-- vref-supply: Phandle to the vref input analog reference voltage.
-- #interrupt-cells = <1>;
-- #address-cells = <1>;
-- #size-cells = <0>;
-
-Optional properties:
-- A pinctrl state named "default" for each ADC channel may be defined to set
-  inX ADC pins in mode of operation for analog input on external pin.
-- booster-supply: Phandle to the embedded booster regulator that can be used
-  to supply ADC analog input switches on stm32h7 and stm32mp1.
-- vdd-supply: Phandle to the vdd input voltage. It can be used to supply ADC
-  analog input switches on stm32mp1.
-- st,syscfg: Phandle to system configuration controller. It can be used to
-  control the analog circuitry on stm32mp1.
-- st,max-clk-rate-hz: Allow to specify desired max clock rate used by analog
-  circuitry.
-
-Contents of a stm32 adc child node:
------------------------------------
-An ADC block node should contain at least one subnode, representing an
-ADC instance available on the machine.
-
-Required properties:
-- compatible: Should be one of:
-  "st,stm32f4-adc"
-  "st,stm32h7-adc"
-  "st,stm32mp1-adc"
-- reg: Offset of ADC instance in ADC block (e.g. may be 0x0, 0x100, 0x200).
-- clocks: Input clock private to this ADC instance. It's required only on
-  stm32f4, that has per instance clock input for registers access.
-- interrupts: IRQ Line for the ADC (e.g. may be 0 for adc@0, 1 for adc@100 or
-  2 for adc@200).
-- st,adc-channels: List of single-ended channels muxed for this ADC.
-  It can have up to 16 channels on stm32f4 or 20 channels on stm32h7, numbered
-  from 0 to 15 or 19 (resp. for in0..in15 or in0..in19).
-- st,adc-diff-channels: List of differential channels muxed for this ADC.
-  Depending on part used, some channels can be configured as differential
-  instead of single-ended (e.g. stm32h7). List here positive and negative
-  inputs pairs as <vinp vinn>, <vinp vinn>,... vinp and vinn are numbered
-  from 0 to 19 on stm32h7)
-  Note: At least one of "st,adc-channels" or "st,adc-diff-channels" is required.
-  Both properties can be used together. Some channels can be used as
-  single-ended and some other ones as differential (mixed). But channels
-  can't be configured both as single-ended and differential (invalid).
-- #io-channel-cells = <1>: See the IIO bindings section "IIO consumers" in
-  Documentation/devicetree/bindings/iio/iio-bindings.txt
-
-Optional properties:
-- dmas: Phandle to dma channel for this ADC instance.
-  See ../../dma/dma.txt for details.
-- dma-names: Must be "rx" when dmas property is being used.
-- assigned-resolution-bits: Resolution (bits) to use for conversions. Must
-  match device available resolutions:
-  * can be 6, 8, 10 or 12 on stm32f4
-  * can be 8, 10, 12, 14 or 16 on stm32h7
-  Default is maximum resolution if unset.
-- st,min-sample-time-nsecs: Minimum sampling time in nanoseconds.
-  Depending on hardware (board) e.g. high/low analog input source impedance,
-  fine tune of ADC sampling time may be recommended.
-  This can be either one value or an array that matches 'st,adc-channels' list,
-  to set sample time resp. for all channels, or independently for each channel.
-
-Example:
-	adc: adc@40012000 {
-		compatible = "st,stm32f4-adc-core";
-		reg = <0x40012000 0x400>;
-		interrupts = <18>;
-		clocks = <&rcc 0 168>;
-		clock-names = "adc";
-		vref-supply = <&reg_vref>;
-		interrupt-controller;
-		pinctrl-names = "default";
-		pinctrl-0 = <&adc3_in8_pin>;
-
-		#interrupt-cells = <1>;
-		#address-cells = <1>;
-		#size-cells = <0>;
-
-		adc@0 {
-			compatible = "st,stm32f4-adc";
-			#io-channel-cells = <1>;
-			reg = <0x0>;
-			clocks = <&rcc 0 168>;
-			interrupt-parent = <&adc>;
-			interrupts = <0>;
-			st,adc-channels = <8>;
-			dmas = <&dma2 0 0 0x400 0x0>;
-			dma-names = "rx";
-			assigned-resolution-bits = <8>;
-		};
-		...
-		other adc child nodes follow...
-	};
-
-Example to setup:
-- channel 1 as single-ended
-- channels 2 & 3 as differential (with resp. 6 & 7 negative inputs)
-
-	adc: adc@40022000 {
-		compatible = "st,stm32h7-adc-core";
-		...
-		adc1: adc@0 {
-			compatible = "st,stm32h7-adc";
-			...
-			st,adc-channels = <1>;
-			st,adc-diff-channels = <2 6>, <3 7>;
-		};
-	};
diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
new file mode 100644
index 00000000..60a0212
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
@@ -0,0 +1,454 @@ 
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/bindings/iio/adc/st,stm32-adc.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: STMicroelectronics STM32 ADC bindings
+
+description: |
+  STM32 ADC is a successive approximation analog-to-digital converter.
+  It has several multiplexed input channels. Conversions can be performed
+  in single, continuous, scan or discontinuous mode. Result of the ADC is
+  stored in a left-aligned or right-aligned 32-bit data register.
+  Conversions can be launched in software or using hardware triggers.
+
+  The analog watchdog feature allows the application to detect if the input
+  voltage goes beyond the user-defined, higher or lower thresholds.
+
+  Each STM32 ADC block can have up to 3 ADC instances.
+
+maintainers:
+  - Fabrice Gasnier <[e-mail]>
+
+properties:
+  compatible:
+    enum:
+      - st,stm32f4-adc-core
+      - st,stm32h7-adc-core
+      - st,stm32mp1-adc-core
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description: |
+      One or more interrupts for ADC block, depending on part used:
+        - stm32f4 and stm32h7 share a common ADC interrupt line.
+        - stm32mp1 has two separate interrupt lines, one for each ADC within
+          ADC block.
+    minItems: 1
+    maxItems: 2
+
+  clocks:
+    description: |
+      Core can use up to two clocks, depending on part used:
+        - "adc" clock: for the analog circuitry, common to all ADCs.
+          It's required on stm32f4.
+          It's optional on stm32h7 and stm32mp1.
+        - "bus" clock: for registers access, common to all ADCs.
+          It's not present on stm32f4.
+          It's required on stm32h7 and stm32mp1.
+
+  clock-names: true
+
+  st,max-clk-rate-hz:
+    description:
+      Allow to specify desired max clock rate used by analog circuitry.
+
+  vdda-supply:
+    description: Phandle to the vdda input analog voltage.
+
+  vref-supply:
+    description: Phandle to the vref input analog reference voltage.
+
+  booster-supply:
+    description:
+      Phandle to the embedded booster regulator that can be used to supply ADC
+      analog input switches on stm32h7 and stm32mp1.
+
+  vdd-supply:
+    description:
+      Phandle to the vdd input voltage. It can be used to supply ADC analog
+      input switches on stm32mp1.
+
+  st,syscfg:
+    description:
+      Phandle to system configuration controller. It can be used to control the
+      analog circuitry on stm32mp1.
+    allOf:
+      - $ref: "/schemas/types.yaml#/definitions/phandle-array"
+
+  interrupt-controller: true
+
+  '#interrupt-cells':
+    const: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: st,stm32f4-adc-core
+
+    then:
+      properties:
+        clocks:
+          maxItems: 1
+
+        clock-names:
+          const: adc
+
+        interrupts:
+          items:
+            - description: interrupt line common for all ADCs
+
+        st,max-clk-rate-hz:
+          minimum: 600000
+          maximum: 36000000
+          default: 36000000
+
+        booster-supply: false
+
+        vdd-supply: false
+
+        st,syscfg: false
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: st,stm32h7-adc-core
+
+    then:
+      properties:
+        clocks:
+          minItems: 1
+          maxItems: 2
+
+        clock-names:
+          items:
+            - const: bus
+            - const: adc
+          minItems: 1
+          maxItems: 2
+
+        interrupts:
+          items:
+            - description: interrupt line common for all ADCs
+
+        st,max-clk-rate-hz:
+          minimum: 120000
+          maximum: 36000000
+          default: 36000000
+
+        vdd-supply: false
+
+        st,syscfg: false
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: st,stm32mp1-adc-core
+
+    then:
+      properties:
+        clocks:
+          minItems: 1
+          maxItems: 2
+
+        clock-names:
+          items:
+            - const: bus
+            - const: adc
+          minItems: 1
+          maxItems: 2
+
+        interrupts:
+          items:
+            - description: interrupt line for ADC1
+            - description: interrupt line for ADC2
+
+        st,max-clk-rate-hz:
+          minimum: 120000
+          maximum: 36000000
+          default: 36000000
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - vdda-supply
+  - vref-supply
+  - interrupt-controller
+  - '#interrupt-cells'
+  - '#address-cells'
+  - '#size-cells'
+
+patternProperties:
+  "^adc@[0-9]+$":
+    type: object
+    description:
+      An ADC block node should contain at least one subnode, representing an
+      ADC instance available on the machine.
+
+    properties:
+      compatible:
+        enum:
+          - st,stm32f4-adc
+          - st,stm32h7-adc
+          - st,stm32mp1-adc
+
+      reg:
+        description: |
+          Offset of ADC instance in ADC block. Valid values are:
+            - 0x0:   ADC1
+            - 0x100: ADC2
+            - 0x200: ADC3 (stm32f4 only)
+        maxItems: 1
+
+      '#io-channel-cells':
+        const: 1
+
+      interrupts:
+        description: |
+          IRQ Line for the ADC instance. Valid values are:
+            - 0 for adc@0
+            - 1 for adc@100
+            - 2 for adc@200 (stm32f4 only)
+        maxItems: 1
+
+      clocks:
+        description:
+          Input clock private to this ADC instance. It's required only on
+          stm32f4, that has per instance clock input for registers access.
+        maxItems: 1
+
+      dmas:
+        description: RX DMA Channel
+        maxItems: 1
+
+      dma-names:
+        const: rx
+
+      assigned-resolution-bits:
+        description: |
+          Resolution (bits) to use for conversions:
+            - can be 6, 8, 10 or 12 on stm32f4
+            - can be 8, 10, 12, 14 or 16 on stm32h7 and stm32mp1
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+
+      st,adc-channels:
+        description: |
+          List of single-ended channels muxed for this ADC. It can have up to:
+            - 16 channels, numbered from 0 to 15 (for in0..in15) on stm32f4
+            - 20 channels, numbered from 0 to 19 (for in0..in19) on stm32h7 and
+              stm32mp1.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32-array
+
+      st,adc-diff-channels:
+        description: |
+          List of differential channels muxed for this ADC. Some channels can
+          be configured as differential instead of single-ended on stm32h7 and
+          on stm32mp1. Positive and negative inputs pairs are listed:
+          <vinp vinn>, <vinp vinn>,... vinp and vinn are numbered from 0 to 19.
+
+          Note: At least one of "st,adc-channels" or "st,adc-diff-channels" is
+          required. Both properties can be used together. Some channels can be
+          used as single-ended and some other ones as differential (mixed). But
+          channels can't be configured both as single-ended and differential.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32-matrix
+          - items:
+              items:
+                - description: |
+                    "vinp" indicates positive input number
+                  minimum: 0
+                  maximum: 19
+                - description: |
+                    "vinn" indicates negative input number
+                  minimum: 0
+                  maximum: 19
+
+      st,min-sample-time-nsecs:
+        description:
+          Minimum sampling time in nanoseconds. Depending on hardware (board)
+          e.g. high/low analog input source impedance, fine tune of ADC
+          sampling time may be recommended. This can be either one value or an
+          array that matches "st,adc-channels" and/or "st,adc-diff-channels"
+          list, to set sample time resp. for all channels, or independently for
+          each channel.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32-array
+
+    allOf:
+      - if:
+          properties:
+            compatible:
+              contains:
+                const: st,stm32f4-adc
+
+        then:
+          properties:
+            reg:
+              enum:
+                - 0x0
+                - 0x100
+                - 0x200
+
+            interrupts:
+              minimum: 0
+              maximum: 2
+
+            assigned-resolution-bits:
+              enum: [6, 8, 10, 12]
+              default: 12
+
+            st,adc-channels:
+              minItems: 1
+              maxItems: 16
+              minimum: 0
+              maximum: 15
+
+            st,adc-diff-channels: false
+
+            st,min-sample-time-nsecs:
+              minItems: 1
+              maxItems: 16
+              minimum: 80
+
+          required:
+            - clocks
+
+      - if:
+          properties:
+            compatible:
+              contains:
+                enum:
+                  - st,stm32h7-adc
+                  - st,stm32mp1-adc
+
+        then:
+          properties:
+            reg:
+              enum:
+                - 0x0
+                - 0x100
+
+            interrupts:
+              minimum: 0
+              maximum: 1
+
+            assigned-resolution-bits:
+              enum: [8, 10, 12, 14, 16]
+              default: 16
+
+            st,adc-channels:
+              minItems: 1
+              maxItems: 20
+              minimum: 0
+              maximum: 19
+
+            st,min-sample-time-nsecs:
+              minItems: 1
+              maxItems: 20
+              minimum: 40
+
+    additionalProperties: false
+
+    anyOf:
+      - required:
+          - st,adc-channels
+      - required:
+          - st,adc-diff-channels
+
+    required:
+      - compatible
+      - reg
+      - interrupts
+      - '#io-channel-cells'
+
+examples:
+  - |
+    // Example 1: with stm32f429
+      adc123: adc@40012000 {
+        compatible = "st,stm32f4-adc-core";
+        reg = <0x40012000 0x400>;
+        interrupts = <18>;
+        clocks = <&rcc 0 168>;
+        clock-names = "adc";
+        st,max-clk-rate-hz = <36000000>;
+        vdda-supply = <&vdda>;
+        vref-supply = <&vref>;
+        interrupt-controller;
+        #interrupt-cells = <1>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        adc@0 {
+          compatible = "st,stm32f4-adc";
+          #io-channel-cells = <1>;
+          reg = <0x0>;
+          clocks = <&rcc 0 168>;
+          interrupt-parent = <&adc123>;
+          interrupts = <0>;
+          st,adc-channels = <8>;
+          dmas = <&dma2 0 0 0x400 0x0>;
+          dma-names = "rx";
+          assigned-resolution-bits = <8>;
+        };
+        // ...
+        // other adc child nodes follow...
+      };
+
+  - |
+    // Example 2: with stm32mp157c to setup ADC1 with:
+    // - channel 1 as single-ended
+    // - channels 2 & 3 as differential (with resp. 6 & 7 negative inputs)
+      #include <dt-bindings/interrupt-controller/arm-gic.h>
+      #include <dt-bindings/clock/stm32mp1-clks.h>
+      adc12: adc@48003000 {
+        compatible = "st,stm32mp1-adc-core";
+        reg = <0x48003000 0x400>;
+        interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>,
+                     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&rcc ADC12>, <&rcc ADC12_K>;
+        clock-names = "bus", "adc";
+        booster-supply = <&booster>;
+        vdd-supply = <&vdd>;
+        vdda-supply = <&vdda>;
+        vref-supply = <&vref>;
+        st,syscfg = <&syscfg>;
+        interrupt-controller;
+        #interrupt-cells = <1>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        adc@0 {
+          compatible = "st,stm32mp1-adc";
+          #io-channel-cells = <1>;
+          reg = <0x0>;
+          interrupt-parent = <&adc12>;
+          interrupts = <0>;
+          st,adc-channels = <1>;
+          st,adc-diff-channels = <2 6>, <3 7>;
+          st,min-sample-time-nsecs = <5000>;
+          dmas = <&dmamux1 9 0x400 0x05>;
+          dma-names = "rx";
+        };
+        // ...
+        // other adc child node follow...
+      };
+
+...