Add bindings that describe Digital Filter for Sigma Delta Modulators. DFSDM allows to connect sigma delta modulators and/or PDM microphones.
Signed-off-by: Arnaud Pouliquen arnaud.pouliquen@st.com --- .../bindings/iio/adc/st,stm32-dfsdm-adc.txt | 125 +++++++++++++++++++++ 1 file changed, 125 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..83937cb --- /dev/null +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-dfsdm-adc.txt @@ -0,0 +1,125 @@ +STMicroelectronics STM32 DFSDM ADC device driver + + +STM32 DFSDM ADC is a sigma delta analog-to-digital converter dedicted to +interface external sigma delta modulators to stm32 micro controlers. +it is mainly targeted for: +- Sigma delta modulators ( motor control, metering...) +- PDM microphones ( audio digital microphone) + +It featured with up to 8 serial digital interface (SPI or Manchester) and +up to 4 filters. + +Each instance of the sub-drivers uses one filter instance. + +Contents of a stm32 dfsdmc root node: +------------------------------------- +Required properties: +- compatible: Should be "st,stm32-dfsdm-adc". +- 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. +- clocks: Clock for the analog circuitry (common to all ADCs). +- clock-names: Must be "adc". + +Optional properties: +- st,clkout-freq: needed 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, 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-pdm" for audio digital microphone. +- reg: Specifies the DFSDM filter instance. +- interrupts: IRQ lines connected to each DFSDM filter instance. +- st,adc-channels: List of single-ended channels muxed for this ADC. +- st,adc-channel-names: List of single-ended channels Name. +- st,dai-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. + +Required properties for "st,stm32-dfsdm-adc" compatibility: +- #io-channel-cells = <1>: See the IIO bindings section "IIO consumers". +- io-channels: from common iio binding. use to pipe external sigma delta + modulator or internal ADC output to dfsdm channel. + +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. Default value is 0. + - "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. default value is 1. + - "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. + to used for multi microphone synchronization. + +Example of a sigma delta adc purpose: + ads1202: simple_sd_adc@0 { + compatible = "sd-modulator"; + #io-channel-cells = <1>; + status = "okay"; + }; + dfsdm: dfsdm@40017000 { + compatible = "st,stm32h7-dfsdm"; + reg = <0x40017000 0x400>; + clocks = <&timer_clk>; + clock-names = "dfsdm"; + + dfsdm_adc0: dfsdm-adc0@0 { + compatible = "st,stm32-dfsdm-adc"; + #io-channel-cells = <1>; + reg = <0>; + interrupts = <110>; + st,adc-channels = <0>; + st,adc-channel-names = "in0"; + st,adc-channel-types = "SPI_R"; + st,adc-channel-clk-src = "CLKOUT"; + io-channels = <&ads1202 0>; + }; + +Example of a pdm microphone purpose: + dfsdm: dfsdm@40017000 { + compatible = "st,stm32h7-dfsdm"; + reg = <0x40017000 0x400>; + clocks = <&timer_clk>; + clock-names = "dfsdm"; + + dfsdm_pdm0: dfsdm-pdm@0 { + compatible = "st,stm32-dfsdm-pdm"; + #sound-dai-cells = <0>; + reg = <0>; + interrupts = <110>; + dmas = <&dmamux1 102 0x400 0x00>; + dma-names = "rx"; + st,adc-channels = <0>; + st,adc-channel-names = "pdm1"; + st,adc-channel-types = "SPI_R"; + st,adc-channel-clk-src = "CLKOUT"; + }; + }