Add bindings that describes STM32 Digital Filter for Sigma Delta Modulators. DFSDM allows to connect sigma delta modulators.
Signed-off-by: Arnaud Pouliquen arnaud.pouliquen@st.com Acked-by: Rob Herring robh@kernel.org --- .../bindings/iio/adc/st,stm32-dfsdm-adc.txt | 127 +++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.txt
diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.txt b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.txt new file mode 100644 index 0000000..4a42d76 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.txt @@ -0,0 +1,127 @@ +STMicroelectronics STM32 DFSDM ADC device driver + + +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. + +Each child node match with a filter instance. + +Contents of a STM32 DFSDM root node: +------------------------------------ +Required properties: +- compatible: Should be "st,stm32h7-dfsdm". +- reg: Offset and length of the DFSDM block register set. +- clocks: IP and serial interfaces clocking. Should be set according + to rcc clock ID and "clock-names". +- clock-names: Input clock name "dfsdm" must be defined, + "audio" is optional. If defined CLKOUT is based on the audio + clock, else "dfsdm" is used. +- #interrupt-cells = <1>; +- #address-cells = <1>; +- #size-cells = <0>; + +Optional properties: +- spi-max-frequency: Requested only for SPI master mode. + SPI clock OUT frequency (Hz). This clock must be set according + to "clock" property. Frequency must be a multiple of the rcc + clock frequency. If not, SPI CLKOUT frequency will not be + accurate. + +Contents of a STM32 DFSDM child nodes: +-------------------------------------- + +Required properties: +- compatible: Must be: + "st,stm32-dfsdm-adc" for sigma delta ADCs + "st,stm32-dfsdm-dmic" for audio digital microphone. +- reg: Specifies the DFSDM filter instance used. +- interrupts: IRQ lines connected to each DFSDM filter instance. +- st,adc-channels: List of single-ended channels muxed for this ADC. + valid values: + "st,stm32h7-dfsdm" compatibility: 0 to 7. +- st,adc-channel-names: List of single-ended channel names. +- st,filter-order: 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. +- #io-channel-cells = <1>: See the IIO bindings section "IIO consumers". + +Required properties for "st,stm32-dfsdm-adc" compatibility: +- io-channels: From common IIO binding. Used to pipe external sigma delta + modulator or internal ADC output to DFSDM channel. + This is not required for "st,stm32-dfsdm-pdm" compatibility as + PDM microphone is binded in Audio DT node. + +Required properties for "st,stm32-dfsdm-pdm" compatibility: +- #sound-dai-cells: Must be set to 0. +- dma: DMA controller phandle and DMA request line associated to the + filter instance (specified by the field "reg") +- dma-names: Must be "rx" + +Optional properties: +- st,adc-channel-types: 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 + - "MANCH_F": manchester codec, falling edge = logic 1 +- st,adc-channel-clk-src: 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). + +- st,adc-alt-channel: Must be defined if two sigma delta modulator 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. + +- st,filter0-sync: Set to 1 to synchronize with DFSDM filter instance 0. + Used for multi microphones synchronization. + +Example of a sigma delta adc connected on DFSDM SPI port 0 +and a pdm microphone connected on DFSDM SPI port 1: + + ads1202: simple_sd_adc@0 { + compatible = "ads1202"; + #io-channel-cells = <1>; + }; + + dfsdm: dfsdm@40017000 { + compatible = "st,stm32h7-dfsdm"; + reg = <0x40017000 0x400>; + clocks = <&rcc DFSDM1_CK>; + clock-names = "dfsdm"; + #address-cells = <1>; + #size-cells = <0>; + + dfsdm_adc0: dfsdm-adc@0 { + compatible = "st,stm32-dfsdm-adc"; + #io-channel-cells = <1>; + reg = <0>; + interrupts = <110>; + st,adc-channels = <0>; + st,adc-channel-names = "sd_adc0"; + st,adc-channel-types = "SPI_F"; + st,adc-channel-clk-src = "CLKOUT"; + io-channels = <&ads1202 0>; + st,filter-order = <3>; + }; + dfsdm_pdm1: dfsdm-pdm@1 { + compatible = "st,stm32-dfsdm-dmic"; + reg = <1>; + interrupts = <111>; + dmas = <&dmamux1 102 0x400 0x00>; + dma-names = "rx"; + st,adc-channels = <1>; + st,adc-channel-names = "dmic1"; + st,adc-channel-types = "SPI_R"; + st,adc-channel-clk-src = "CLKOUT"; + st,filter-order = <5>; + }; + }