# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/adc/st,stm32-dfsdm-adc.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: STMicroelectronics STM32 DFSDM ADC device driver
maintainers:
- Fabrice Gasnier <fabrice.gasnier@foss.st.com>
- Olivier Moysan <olivier.moysan@foss.st.com>
description: |
STM32 DFSDM ADC is a sigma delta analog-to-digital converter dedicated to
interface external sigma delta modulators to STM32 micro controllers.
It is mainly targeted for:
- Sigma delta modulators (motor control, metering...)
- PDM microphones (audio digital microphone)
It features up to 8 serial digital interfaces (SPI or Manchester) and
up to 4 filters on stm32h7 or 6 filters on stm32mp1.
Each child node matches with a filter instance.
properties:
compatible:
enum:
- st,stm32h7-dfsdm
- st,stm32mp1-dfsdm
reg:
maxItems: 1
clocks:
items:
- description:
Internal clock used for DFSDM digital processing and control blocks.
dfsdm clock can also feed CLKOUT, when CLKOUT is used.
- description: audio clock can be used as an alternate to feed CLKOUT.
minItems: 1
clock-names:
items:
- const: dfsdm
- const: audio
minItems: 1
"#address-cells":
const: 1
"#size-cells":
const: 0
spi-max-frequency:
description:
SPI clock OUT frequency (Hz). Requested only for SPI master mode.
This clock must be set according to the "clock" property.
Frequency must be a multiple of the rcc clock frequency.
If not, SPI CLKOUT frequency will not be accurate.
maximum: 20000000
required:
- compatible
- reg
- clocks
- clock-names
- "#address-cells"
- "#size-cells"
additionalProperties: false
patternProperties:
"^filter@[0-9]+$":
type: object
unevaluatedProperties: false
description: child node
properties:
compatible:
enum:
- st,stm32-dfsdm-adc
- st,stm32-dfsdm-dmic
reg:
description: Specifies the DFSDM filter instance used.
maxItems: 1
interrupts:
maxItems: 1
st,adc-channels:
description: |
List of single-ended channels muxed for this ADC.
On stm32h7 and stm32mp1:
- For st,stm32-dfsdm-adc: up to 8 channels numbered from 0 to 7.
- For st,stm32-dfsdm-dmic: 1 channel numbered from 0 to 7.
$ref: /schemas/types.yaml#/definitions/uint32-array
items:
minimum: 0
maximum: 7
st,adc-channel-names:
description: List of single-ended channel names.
st,filter-order:
description: |
SinC filter order from 0 to 5.
- 0: FastSinC
- [1-5]: order 1 to 5.
For audio purpose it is recommended to use order 3 to 5.
$ref: /schemas/types.yaml#/definitions/uint32
maximum: 5
"#io-channel-cells":
const: 1
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 ]
$ref: /schemas/types.yaml#/definitions/non-unique-string-array
st,adc-alt-channel:
description:
Must be defined if two sigma delta modulators are
connected on same SPI input.
If not set, channel n is connected to SPI input n.
If set, channel n is connected to SPI input n + 1.
type: boolean
st,filter0-sync:
description:
Set to 1 to synchronize with DFSDM filter instance 0.
Used for multi microphones synchronization.
type: boolean
dmas:
maxItems: 1
dma-names:
items:
- const: rx
required:
- compatible
- reg
- interrupts
- st,adc-channels
- st,adc-channel-names
- st,filter-order
- "#io-channel-cells"
allOf:
- if:
properties:
compatible:
contains:
const: st,stm32-dfsdm-adc
then:
properties:
st,adc-channels:
minItems: 1
maxItems: 8
st,adc-channel-names:
minItems: 1
maxItems: 8
st,adc-channel-types:
minItems: 1
maxItems: 8
st,adc-channel-clk-src:
minItems: 1
maxItems: 8
io-channels:
description:
From common IIO binding. Used to pipe external sigma delta
modulator or internal ADC output to DFSDM channel.
required:
- io-channels
- if:
properties:
compatible:
contains:
const: st,stm32-dfsdm-dmic
then:
properties:
st,adc-channels:
maxItems: 1
st,adc-channel-names:
maxItems: 1
st,adc-channel-types:
maxItems: 1
st,adc-channel-clk-src:
maxItems: 1
required:
- dmas
- dma-names
patternProperties:
"^dfsdm-dai+$":
type: object
additionalProperties: false
description: child node
properties:
compatible:
enum:
- st,stm32h7-dfsdm-dai
"#sound-dai-cells":
const: 0
io-channels:
description:
From common IIO binding. Used to pipe external sigma delta
modulator or internal ADC output to DFSDM channel.
required:
- compatible
- "#sound-dai-cells"
- io-channels
allOf:
- if:
properties:
compatible:
contains:
const: st,stm32h7-dfsdm
then:
patternProperties:
"^filter@[0-9]+$":
properties:
reg:
items:
minimum: 0
maximum: 3
- if:
properties:
compatible:
contains:
const: st,stm32mp1-dfsdm
then:
patternProperties:
"^filter@[0-9]+$":
properties:
reg:
items:
minimum: 0
maximum: 5
examples:
- |
#include <dt-bindings/interrupt-controller/arm-gic.h>
#include <dt-bindings/clock/stm32mp1-clks.h>
dfsdm: 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>;
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>;
st,adc-channels = <1>;
st,adc-channel-names = "dmic0";
st,adc-channel-types = "SPI_R";
st,adc-channel-clk-src = "CLKOUT";
st,filter-order = <5>;
asoc_pdm0: dfsdm-dai {
compatible = "st,stm32h7-dfsdm-dai";
#sound-dai-cells = <0>;
io-channels = <&dfsdm0 0>;
};
};
dfsdm_pdm1: 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>;
};
};
...