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

From: Fabrice Gasnier
Date: Fri Dec 06 2019 - 11:19:36 EST


On 12/5/19 11:24 PM, Rob Herring wrote:
> On Wed, Nov 27, 2019 at 05:48:45PM +0100, Fabrice Gasnier wrote:
>> Convert the STM32 ADC binding to DT schema format using json-schema
>>
>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
>> ---
>> Note: this applies on top of IIO tree currently (iio-for-5.5c).
>> ---
>> .../devicetree/bindings/iio/adc/st,stm32-adc.txt | 149 -------
>> .../devicetree/bindings/iio/adc/st,stm32-adc.yaml | 448 +++++++++++++++++++++
>> 2 files changed, 448 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..2ebc2e6
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml
>> @@ -0,0 +1,448 @@
>> +# 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 <fabrice.gasnier@xxxxxx>
>> +
>> +properties:
>> + compatible:
>> + enum:
>> + - st,stm32f4-adc-core
>> + - st,stm32h7-adc-core
>> + - st,stm32mp1-adc-core
>> +
>> + reg:
>> + description: Offset and length of the ADC block register set
>
> Don't need generic description of a standard property.

Hi Rob,

ok

>
>> + 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.
>
> You can put minItems: 1, maxItems: 2 here.

ok

>
>> +
>> + 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.
>> + allOf:
>> + - $ref: /schemas/types.yaml#/definitions/uint32
>
> *-hz already has a type, so you can drop this.
>
> No range you can specify?

Yes, I'll add it in V2 under the if sections bellow as it depends on the
STM32 device (compatible).

>
>> +
>> + vdda-supply:
>> + description: Phandle to the vdda input analog voltage.
>> +
>> + vref-supply:
>> + description: Phandle to the vref input analog reference voltage.
>> +
>> + booster-supply:
>> + description: |
>
> There's not any formatting here, so '|' can be dropped.

ok, I'll remove it also at few places

>
>> + 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:
>> + items:
>> + const: adc
>> + maxItems: 1
>
> You can simplify to:
>
> clock-names:
> const: adc
>
> Note that if you did have 'items' it should be a list (i.e. have '-').

ok

>
>> +
>> + interrupts:
>> + items:
>> + - description: interrupt line common for all ADCs
>> +
>> + 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
>> +
>> + 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
>> +
>> +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
>
> There's a lot of if/thens in this binding. I wonder if splitting this
> into 2 files might be cleaner.

Indeed there are a lot of these... But there is also several common
descriptions (the core remains similar).
Do you mind if I keep it that way ?

Let's discuss that in V2 otherwise.
In case we're going to split this:
- I think the most similar ADCs are STM32H7 and STM32MP1
- The STM32F4 ADC bindings should then be apart.

>
>> +
>> + then:
>> + properties:
>> + reg:
>> + enum:
>> + - 0x0
>> + - 0x100
>> + - 0x200
>> +
>> + interrupts:
>> + minimum: 0
>> + maximum: 2
>> +
>> + assigned-resolution-bits:
>> + allOf:
>> + - enum: [6, 8, 10, 12]
>> + - default: 12
>> +
>> + st,adc-channels:
>> + allOf:
>> + - maxItems: 16
>> + items:
>> + minimum: 0
>> + maximum: 15
>> +
>> + st,adc-diff-channels: false
>> +
>> + st,min-sample-time-nsecs:
>> + allOf:
>> + - maxItems: 16
>> + items:
>> + 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:
>> + allOf:
>
> Shouldn't need the allOf here.

ok

>
>> + - enum: [8, 10, 12, 14, 16]
>> + - default: 16
>> +
>> + st,adc-channels:
>> + allOf:
>
> Shouldn't need the allOf here.

ok

>
>> + - maxItems: 20
>> + items:
>> + minimum: 0
>> + maximum: 19
>> +
>> + st,min-sample-time-nsecs:
>> + allOf:
>
> Shouldn't need the allOf here.

ok

>
>> + - maxItems: 20
>> + items:
>> + 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
>>