Re: [alsa-devel] [PATCH v6 07/13] IIO: add DT bindings for stm32 DFSDM filter

On Fri, 1 Dec 2017 18:40:14 +0100 Arnaud Pouliquen arnaud.pouliquen@st.com wrote:

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

Acked-by: Jonathan Cameron Jonathan.Cameron@huawei.com

---

.../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>;
  

• };
  

• }