STMicroelectronics Audio Digital Filter Sigma Delta modulators(DFSDM) The DFSDM allows PDM microphones capture through SPI interface. The Audio interface is seems as a sub block of the DFSDM device. For details on DFSDM bindings refer to ../iio/adc/st,stm32-dfsdm-adc.txt Required properties: - compatible: "st,stm32h7-dfsdm-dai". - #sound-dai-cells : Must be equal to 0 - io-channels : phandle to iio dfsdm instance node. Example of a sound card using audio DFSDM node. sound_card { compatible = "audio-graph-card"; dais = <&cpu_port>; }; dfsdm: dfsdm@40017000 { compatible = "st,stm32h7-dfsdm"; reg = <0x40017000 0x400>; clocks = <&rcc DFSDM1_CK>; clock-names = "dfsdm"; #interrupt-cells = <1>; #address-cells = <1>; #size-cells = <0>; dfsdm_adc0: filter@0 { compatible = "st,stm32-dfsdm-dmic"; reg = <0>; interrupts = <110>; dmas = <&dmamux1 101 0x400 0x00>; dma-names = "rx"; 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>; dfsdm_dai0: dfsdm-dai { compatible = "st,stm32h7-dfsdm-dai"; #sound-dai-cells = <0>; io-channels = <&dfsdm_adc0 0>; cpu_port: port { dfsdm_endpoint: endpoint { remote-endpoint = <&dmic0_endpoint>; }; }; }; }; dmic0: dmic@0 { compatible = "dmic-codec"; #sound-dai-cells = <0>; port { dmic0_endpoint: endpoint { remote-endpoint = <&dfsdm_endpoint>; }; }; };