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@xxxxxx>
---
.../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";
+ };
+ }
--
1.9.1
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