[PATCH v6 0/9] iio: adc: dfsdm: add scaling support
The aim of this serie is to add scaling support to STM32 DFSDM peripheral in the analog context.
The DFSDM currently operates as a consumer of IIO channels provided by a generic SD modulator. As previously discussed in RFC [1], this topology is not suitable for implementing scaling.
This series brings the integration of the DFSDM driver with the new IIO backend framework [2], enabling the DFSDM IIO device to offer scaling feature based on reference voltage data obtained from the IIO SD modulator backend. This generic SD modulator backend takes the place of the former SD modulator, used with legacy implementation.
The DFSDM driver has been updated to adopt the generic ADC channel binding [3]. The reasons for this include: - Reducing the use of proprietary properties - Simplifying the coexistence of legacy and new backend bindings - Prepare the support of the MDF peripheral on STM32MP25 SoC
Backward compatibility is maintained through legacy support.
This series extends the backend framework with the following APIs: - iio_backend_read_raw: This API is intented to retrieve channel attributes from the backend. It is based on IIO framework read_raw API. - iio_backend_read_scale / iio_backend_read_offset Dedicated APIs to read scale and offset channel values. - iio_backend_disable / iio_backend_enable: backend enable/disable to be used for PM management - devm_iio_backend_fwnode_get Intended for parsing DT subnodes to allow generic channel binding support, as generic channel DT nodes are not populated as devices.
[1]: https://lore.kernel.org/lkml/20200204101008.11411-1-olivier.moysan@st.com/ [2]: https://lore.kernel.org/all/20240206-iio-backend-v9-0-df66d159c000@analog.co... [3]: devicetree/bindings/iio/adc/adc.yaml
Changes in v2: - Update enable/disable backend API - Rename devm_iio_backend_subnode_get(), as devm_iio_backend_fwnode_get() - Update iio_backend_read_raw() prototype to fully match IIO framework read_raw callback prototype. - Change st,adc-channel-type property name and type in DFSDM binding - Remove sd-backend and rename ads1201 compatibles in SD binding
Changes in v3: - Add iio_backend_read_scale and iio_backend_read_offset - Remove sd-backend compatible. Adapt existing sd modulator driver and binding to support backend topology. - Misc corrections in DFSDM binding & minor changes in DFSDM driver
Changes in v4: - Remove allOf and rework examples in SD modulator binding - Wrap lines to 80 characters in IIO code
Changes in v5: - Move iio_backend_read_scale and iio_backend_read_offset to inline and update prototype - Fix channel number & remove legacy binding example in DFSDM binding - Rearrange DFSDM patches to fix build issue in serie - Split SD modulator binding patch. Move reference voltage change in a separate patch
Changes in v6: - Minor cleanup in DFSDM binding - Fix vref-supply dependency condition in SD modulator binding
Olivier Moysan (9): iio: add read scale and offset services to iio backend framework iio: add enable and disable services to iio backend framework iio: add child nodes support in iio backend framework dt-bindings: iio: dfsdm: move to backend framework dt-bindings: iio: add backend support to sd modulator dt-bindings: iio: add vref support to sd modulator iio: adc: stm32-dfsdm: adopt generic channels bindings iio: add iio backend support to sd modulator iio: adc: stm32-dfsdm: add scaling support to dfsdm
.../iio/adc/sigma-delta-modulator.yaml | 25 +- .../bindings/iio/adc/st,stm32-dfsdm-adc.yaml | 122 +++++++- drivers/iio/adc/Kconfig | 2 + drivers/iio/adc/sd_adc_modulator.c | 92 +++++- drivers/iio/adc/stm32-dfsdm-adc.c | 293 +++++++++++++++--- drivers/iio/industrialio-backend.c | 101 +++++- include/linux/iio/backend.h | 29 +- 7 files changed, 592 insertions(+), 72 deletions(-)
base-commit: bf829a98bc4bb9076a2fd70f4a69ea7e281863fa
Change the DFSDM binding to use the new IIO backend framework, along with the adoption of IIO generic channels. This binding change allows to add scaling support to the DFSDM.
Keep the legacy binding as deprecated for backward compatibility.
The io-backends property is supported only in generic IIO channel binding.
- Channel description with the generic binding (Audio and Analog):
Properties superseded by generic properties: st,adc-channels: becomes "reg" property in channel node st,adc-channel-names: becomes "label" property in channel node Properties moved to channel child node: st,adc-channel-types: becomes st,adc-channel-type st,adc-channel-clk-src, st,adc-alt-channel
- Analog binding:
DFSDM filter channel is configured as an IIO backend consumer. Add io-backends property in channel child nodes.
DFSDM is no more configured as a channel consumer from SD modulator. Use of io-channels in DFSDM node is deprecated.
- Audio binding:
DFSDM audio DAI is configured as a channel consumer from DFSDM filter. No change compare to legacy.
Signed-off-by: Olivier Moysan olivier.moysan@foss.st.com Reviewed-by: Rob Herring (Arm) robh@kernel.org --- .../bindings/iio/adc/st,stm32-dfsdm-adc.yaml | 122 +++++++++++++++--- 1 file changed, 107 insertions(+), 15 deletions(-)
diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml index 2722edab1d9a..c24ac98bbb3d 100644 --- a/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.yaml @@ -102,9 +102,11 @@ patternProperties: items: minimum: 0 maximum: 7 + deprecated: true
st,adc-channel-names: description: List of single-ended channel names. + deprecated: true
st,filter-order: description: | @@ -118,6 +120,12 @@ patternProperties: "#io-channel-cells": const: 1
+ '#address-cells': + const: 1 + + '#size-cells': + const: 0 + st,adc-channel-types: description: | Single-ended channel input type. @@ -128,6 +136,7 @@ patternProperties: items: enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ] $ref: /schemas/types.yaml#/definitions/non-unique-string-array + deprecated: true
st,adc-channel-clk-src: description: | @@ -139,6 +148,7 @@ patternProperties: items: enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ] $ref: /schemas/types.yaml#/definitions/non-unique-string-array + deprecated: true
st,adc-alt-channel: description: @@ -147,6 +157,7 @@ patternProperties: If not set, channel n is connected to SPI input n. If set, channel n is connected to SPI input n + 1. type: boolean + deprecated: true
st,filter0-sync: description: @@ -165,11 +176,60 @@ patternProperties: - compatible - reg - interrupts - - st,adc-channels - - st,adc-channel-names - st,filter-order - "#io-channel-cells"
+ patternProperties: + "^channel@[0-7]$": + type: object + $ref: adc.yaml + unevaluatedProperties: false + description: Represents the external channels which are connected to the DFSDM. + + properties: + reg: + maximum: 7 + + label: + description: + Unique name to identify which channel this is. + + st,adc-channel-type: + description: | + Single-ended channel input type. + - "SPI_R": SPI with data on rising edge (default) + - "SPI_F": SPI with data on falling edge + - "MANCH_R": manchester codec, rising edge = logic 0, falling edge = logic 1 + - "MANCH_F": manchester codec, rising edge = logic 1, falling edge = logic 0 + $ref: /schemas/types.yaml#/definitions/string + enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ] + + st,adc-channel-clk-src: + description: | + Conversion clock source. + - "CLKIN": external SPI clock (CLKIN x) + - "CLKOUT": internal SPI clock (CLKOUT) (default) + - "CLKOUT_F": internal SPI clock divided by 2 (falling edge). + - "CLKOUT_R": internal SPI clock divided by 2 (rising edge). + $ref: /schemas/types.yaml#/definitions/string + enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ] + + st,adc-alt-channel: + description: + Must be defined if two sigma delta modulators are + connected on same SPI input. + If not set, channel n is connected to SPI input n. + If set, channel n is connected to SPI input n + 1. + type: boolean + + io-backends: + description: + Used to pipe external sigma delta modulator or internal ADC backend to DFSDM channel. + maxItems: 1 + + required: + - reg + allOf: - if: properties: @@ -199,9 +259,19 @@ patternProperties: description: From common IIO binding. Used to pipe external sigma delta modulator or internal ADC output to DFSDM channel. + deprecated: true
- required: - - io-channels + if: + required: + - st,adc-channels + then: + required: + - io-channels + + patternProperties: + "^channel@[0-7]$": + required: + - io-backends
- if: properties: @@ -298,6 +368,7 @@ examples: #address-cells = <1>; #size-cells = <0>;
+ // Example 1: Audio use case with generic binding dfsdm0: filter@0 { compatible = "st,stm32-dfsdm-dmic"; reg = <0>; @@ -305,12 +376,18 @@ examples: dmas = <&dmamux1 101 0x400 0x01>; dma-names = "rx"; #io-channel-cells = <1>; - st,adc-channels = <1>; - st,adc-channel-names = "dmic0"; - st,adc-channel-types = "SPI_R"; - st,adc-channel-clk-src = "CLKOUT"; + #address-cells = <1>; + #size-cells = <0>; st,filter-order = <5>;
+ channel@1 { + reg = <1>; + label = "dmic0"; + st,adc-channel-type = "SPI_R"; + st,adc-channel-clk-src = "CLKOUT"; + st,adc-alt-channel; + }; + asoc_pdm0: dfsdm-dai { compatible = "st,stm32h7-dfsdm-dai"; #sound-dai-cells = <0>; @@ -318,19 +395,34 @@ examples: }; };
- dfsdm_pdm1: filter@1 { + // Example 2: Analog use case with generic binding + dfsdm1: filter@1 { compatible = "st,stm32-dfsdm-adc"; reg = <1>; interrupts = <GIC_SPI 111 IRQ_TYPE_LEVEL_HIGH>; dmas = <&dmamux1 102 0x400 0x01>; dma-names = "rx"; - #io-channel-cells = <1>; - st,adc-channels = <2 3>; - st,adc-channel-names = "in2", "in3"; - st,adc-channel-types = "SPI_R", "SPI_R"; - st,adc-channel-clk-src = "CLKOUT_F", "CLKOUT_F"; - io-channels = <&sd_adc2 &sd_adc3>; st,filter-order = <1>; + #io-channel-cells = <1>; + #address-cells = <1>; + #size-cells = <0>; + + channel@2 { + reg = <2>; + label = "in2"; + st,adc-channel-type = "SPI_F"; + st,adc-channel-clk-src = "CLKOUT"; + st,adc-alt-channel; + io-backends = <&sd_adc2>; + }; + + channel@3 { + reg = <3>; + label = "in3"; + st,adc-channel-type = "SPI_R"; + st,adc-channel-clk-src = "CLKOUT"; + io-backends = <&sd_adc3>; + }; }; };
On Tue, 30 Jul 2024 10:46:30 +0200 Olivier Moysan olivier.moysan@foss.st.com wrote:
The aim of this serie is to add scaling support to STM32 DFSDM peripheral in the analog context.
All looks good to me. I'll leave it a little longer though as some of the dt-bindings patches don't have tags from the maintainers yet.
Jonathan
On Sat, 3 Aug 2024 16:13:34 +0100 Jonathan Cameron jic23@kernel.org wrote:
On Tue, 30 Jul 2024 10:46:30 +0200 Olivier Moysan olivier.moysan@foss.st.com wrote:
The aim of this serie is to add scaling support to STM32 DFSDM peripheral in the analog context.
All looks good to me. I'll leave it a little longer though as some of the dt-bindings patches don't have tags from the maintainers yet.
Jonathan
Applied to the togreg branch of iio.git and pushed out as testing for 0-day to poke at it etc.
Thanks,
Jonathan
participants (2)
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Jonathan Cameron -
Olivier Moysan