[PATCH 0/8] 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 (which may need further refinement): - read_raw: This API is intented to retrieve the voltage information from the backend. It is based on IIO read_raw API, but maybe we need a more specialized API here. - iio_backend_disable / iio_backend_enable: backend enable/disable to be used for PM management - devm_iio_backend_subnode_get Intended for parsing DT subnodes to allow generic channel binding support, as generic channel DT nodes are not populated as devices. Ideally, a single API would be better, but I could not identify a suitable alternative that doesn't affect the existing API (devm_iio_backend_get).
[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
Olivier Moysan (8): iio: add read raw service 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 sigma delta modulator backend iio: adc: stm32-dfsdm: adopt generic channels bindings iio: add sd modulator generic iio backend iio: adc: stm32-dfsdm: add scaling support to dfsdm
.../iio/adc/sd-modulator-backend.yaml | 43 +++ .../bindings/iio/adc/st,stm32-dfsdm-adc.yaml | 158 ++++++++- drivers/iio/adc/Kconfig | 11 + drivers/iio/adc/Makefile | 1 + drivers/iio/adc/sd_adc_backend.c | 110 +++++++ drivers/iio/adc/stm32-dfsdm-adc.c | 302 +++++++++++++++--- drivers/iio/industrialio-backend.c | 90 +++++- include/linux/iio/backend.h | 7 + 8 files changed, 664 insertions(+), 58 deletions(-) create mode 100644 Documentation/devicetree/bindings/iio/adc/sd-modulator-backend.yaml create mode 100644 drivers/iio/adc/sd_adc_backend.c
base-commit: 7db8a847f98caae68c70bdab9ba92d1af38e5656
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 supersed 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, 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 --- .../bindings/iio/adc/st,stm32-dfsdm-adc.yaml | 158 +++++++++++++++++- 1 file changed, 152 insertions(+), 6 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 c1b1324fa132..dd414bab74c1 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 ] $ref: /schemas/types.yaml#/definitions/non-unique-string-array + deprecated: true
st,adc-alt-channel: description: @@ -147,6 +157,7 @@ patternProperties: If not set, channel n is connected to SPI input n. If set, channel n is connected to SPI input n + 1. type: boolean + deprecated: true
st,filter0-sync: description: @@ -165,11 +176,65 @@ patternProperties: - compatible - reg - interrupts - - st,adc-channels - - st,adc-channel-names - st,filter-order - "#io-channel-cells"
+ patternProperties: + "^channel@([0-9]|1[0-9])$": + type: object + $ref: adc.yaml + description: Represents the external channels which are connected to the DFSDM. + + properties: + reg: + items: + minimum: 0 + maximum: 8 + + label: + description: + Unique name to identify which channel this is. + + st,adc-channel-types: + 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 + items: + enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ] + $ref: /schemas/types.yaml#/definitions/non-unique-string-array + + 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). + items: + enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ] + $ref: /schemas/types.yaml#/definitions/non-unique-string-array + + st,adc-alt-channel: + description: + Must be defined if two sigma delta modulators are + connected on same SPI input. + If not set, channel n is connected to SPI input n. + If set, channel n is connected to SPI input n + 1. + type: boolean + + io-backends: + description: + From common IIO binding. Used to pipe external sigma delta + modulator or internal ADC backend to DFSDM channel. + + required: + - reg + + additionalProperties: false + allOf: - if: properties: @@ -199,9 +264,19 @@ patternProperties: description: From common IIO binding. Used to pipe external sigma delta modulator or internal ADC output to DFSDM channel. + deprecated: true
- required: - - io-channels + if: + required: + - st,adc-channels + then: + required: + - io-channels + + patternProperties: + "^channel@([0-9]|1[0-9])$": + required: + - io-backends
- if: properties: @@ -294,7 +369,77 @@ 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>; + interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_HIGH>; + dmas = <&dmamux1 101 0x400 0x01>; + dma-names = "rx"; + #io-channel-cells = <1>; + #address-cells = <1>; + #size-cells = <0>; + st,filter-order = <5>; + + channel@1 { + reg = <1>; + label = "dmic0"; + st,adc-channel-types = "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>; + io-channels = <&dfsdm0 0>; + }; + }; + + // Example 1: 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"; + st,filter-order = <1>; + #io-channel-cells = <1>; + #address-cells = <1>; + #size-cells = <0>; + + channel@2 { + reg = <2>; + label = "in2"; + st,adc-channel-types = "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-types = "SPI_R"; + st,adc-channel-clk-src = "CLKOUT"; + io-backends = <&sd_adc3>; + }; + }; + }; + + - | + #include <dt-bindings/interrupt-controller/arm-gic.h> + #include <dt-bindings/clock/stm32mp1-clks.h> + dfsdm_2: dfsdm@4400d000 { + compatible = "st,stm32mp1-dfsdm"; + reg = <0x4400d000 0x800>; + clocks = <&rcc DFSDM_K>, <&rcc ADFSDM_K>; + clock-names = "dfsdm", "audio"; + #address-cells = <1>; + #size-cells = <0>; + + // Example 3: Audio use case with legacy binding + dfsdm0_2: filter@0 { compatible = "st,stm32-dfsdm-dmic"; reg = <0>; interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_HIGH>; @@ -307,14 +452,15 @@ examples: st,adc-channel-clk-src = "CLKOUT"; st,filter-order = <5>;
- asoc_pdm0: dfsdm-dai { + asoc_pdm0_2: dfsdm-dai { compatible = "st,stm32h7-dfsdm-dai"; #sound-dai-cells = <0>; io-channels = <&dfsdm0 0>; }; };
- dfsdm_pdm1: filter@1 { + // Example 3: Analog use case with legacy binding + dfsdm1_2: filter@1 { compatible = "st,stm32-dfsdm-adc"; reg = <1>; interrupts = <GIC_SPI 111 IRQ_TYPE_LEVEL_HIGH>;
On Tue, Jun 18, 2024 at 06:08:30PM +0200, Olivier Moysan wrote:
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 supersed 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, 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
.../bindings/iio/adc/st,stm32-dfsdm-adc.yaml | 158 +++++++++++++++++- 1 file changed, 152 insertions(+), 6 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 c1b1324fa132..dd414bab74c1 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 ] $ref: /schemas/types.yaml#/definitions/non-unique-string-array
deprecated: true st,adc-alt-channel: description:
@@ -147,6 +157,7 @@ patternProperties: If not set, channel n is connected to SPI input n. If set, channel n is connected to SPI input n + 1. type: boolean
deprecated: true st,filter0-sync: description:
@@ -165,11 +176,65 @@ patternProperties: - compatible - reg - interrupts
- st,adc-channels
- st,adc-channel-names - st,filter-order - "#io-channel-cells"
- patternProperties:
"^channel@([0-9]|1[0-9])$":
type: object
$ref: adc.yaml
description: Represents the external channels which are connected to the DFSDM.
properties:
reg:
items:
minimum: 0
maximum: 8
label:
description:
Unique name to identify which channel this is.
st,adc-channel-types:
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
items:
enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ]
$ref: /schemas/types.yaml#/definitions/non-unique-string-array
Why is this an array? And why is the property plural? Can a channel have more than one type?
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).
items:
enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ]
$ref: /schemas/types.yaml#/definitions/non-unique-string-array
Ditto here, but s/type/clock source/
Thanks, Conor.
st,adc-alt-channel:
description:
Must be defined if two sigma delta modulators are
connected on same SPI input.
If not set, channel n is connected to SPI input n.
If set, channel n is connected to SPI input n + 1.
type: boolean
io-backends:
description:
From common IIO binding.
Drop this from the description.
Used to pipe external sigma delta
modulator or internal ADC backend to DFSDM channel.
required:
- reg
additionalProperties: false
- allOf: - if: properties:
@@ -199,9 +264,19 @@ patternProperties: description: From common IIO binding. Used to pipe external sigma delta modulator or internal ADC output to DFSDM channel.
deprecated: true
required:
- io-channels
if:
required:
- st,adc-channels
then:
required:
- io-channels
patternProperties:
"^channel@([0-9]|1[0-9])$":
required:
- io-backends
Why is this here, rather than with reg above? Only some channels require a backend?
Hi Conor,
On 6/18/24 20:10, Conor Dooley wrote:
On Tue, Jun 18, 2024 at 06:08:30PM +0200, Olivier Moysan wrote:
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 supersed 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, 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
.../bindings/iio/adc/st,stm32-dfsdm-adc.yaml | 158 +++++++++++++++++- 1 file changed, 152 insertions(+), 6 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 c1b1324fa132..dd414bab74c1 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 ] $ref: /schemas/types.yaml#/definitions/non-unique-string-array
deprecated: true st,adc-alt-channel: description:
@@ -147,6 +157,7 @@ patternProperties: If not set, channel n is connected to SPI input n. If set, channel n is connected to SPI input n + 1. type: boolean
deprecated: true st,filter0-sync: description:
@@ -165,11 +176,65 @@ patternProperties: - compatible - reg - interrupts
- st,adc-channels
- st,adc-channel-names - st,filter-order - "#io-channel-cells"
- patternProperties:
"^channel@([0-9]|1[0-9])$":
type: object
$ref: adc.yaml
description: Represents the external channels which are connected to the DFSDM.
properties:
reg:
items:
minimum: 0
maximum: 8
label:
description:
Unique name to identify which channel this is.
st,adc-channel-types:
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
items:
enum: [ SPI_R, SPI_F, MANCH_R, MANCH_F ]
$ref: /schemas/types.yaml#/definitions/non-unique-string-array
Why is this an array? And why is the property plural? Can a channel have more than one type?
You are right. In channel node context, this property is no more an array. It has to be managed as a single string (This is already the case in the driver). I will change the type in binding and the name, to reflect this.
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).
items:
enum: [ CLKIN, CLKOUT, CLKOUT_F, CLKOUT_R ]
$ref: /schemas/types.yaml#/definitions/non-unique-string-array
Ditto here, but s/type/clock source/
Same here.
Thanks, Conor.
st,adc-alt-channel:
description:
Must be defined if two sigma delta modulators are
connected on same SPI input.
If not set, channel n is connected to SPI input n.
If set, channel n is connected to SPI input n + 1.
type: boolean
io-backends:
description:
From common IIO binding.
Drop this from the description.
Used to pipe external sigma delta
modulator or internal ADC backend to DFSDM channel.
required:
- reg
additionalProperties: false
allOf: - if: properties:
@@ -199,9 +264,19 @@ patternProperties: description: From common IIO binding. Used to pipe external sigma delta modulator or internal ADC output to DFSDM channel.
deprecated: true
required:
- io-channels
if:
required:
- st,adc-channels
then:
required:
- io-channels
patternProperties:
"^channel@([0-9]|1[0-9])$":
required:
- io-backends
Why is this here, rather than with reg above? Only some channels require a backend?
The io-backends property is required only when we use st,stm32-dfsdm-adc compatible. In other words, when we are in an analog use case. In this case the channel is a consumer of a backend (typically a sd modulator) In an audio use case (compatible st,stm32-dfsdm-dmic) the backend is not required.
BRs Olivier
On Thu, Jun 20, 2024 at 10:03:44AM +0200, Olivier MOYSAN wrote:
On 6/18/24 20:10, Conor Dooley wrote:
On Tue, Jun 18, 2024 at 06:08:30PM +0200, Olivier Moysan wrote:
allOf: - if: properties:
@@ -199,9 +264,19 @@ 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@([0-9]|1[0-9])$":
required:
- io-backends
Why is this here, rather than with reg above? Only some channels require a backend?
The io-backends property is required only when we use st,stm32-dfsdm-adc compatible. In other words, when we are in an analog use case. In this case the channel is a consumer of a backend (typically a sd modulator) In an audio use case (compatible st,stm32-dfsdm-dmic) the backend is not required.
Ahh, I think the hunks and indent confused me here. What you're doing is making io-backends required based on the compatible, but what I thought you were doing was trying to make io-backends required in channels if st,adc-channels was set.
Thanks for the explanation, Conor.
On Tue, 18 Jun 2024 18:08:30 +0200 Olivier Moysan olivier.moysan@foss.st.com wrote:
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 supersed by generic properties:
superseded
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, 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
participants (4)
-
Conor Dooley
-
Conor Dooley
-
Jonathan Cameron
-
Olivier Moysan