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

Jonathan Cameron
2017-12-02T14:55:03Z

On Fri, 1 Dec 2017 18:40:14 +0100
Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org> 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-qxv4g6HH51o@public.gmane.org>
> Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Acked-by: Jonathan Cameron <Jonathan.Cameron-hv44wF8Li93QT0dZR+AlfA@public.gmane.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>;
> + };
> + }