linux/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32
Arnaud Pouliquen eca949800d
IIO: ADC: add stm32 DFSDM support for PDM microphone
This code offers a way to handle PDM audio microphones in
ASOC framework. Audio driver should use consumer API.
A specific management is implemented for DMA, with a
callback, to allows to handle audio buffers efficiently.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2018-01-10 10:30:13 +00:00

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What: /sys/bus/iio/devices/iio:deviceX/in_voltage_spi_clk_freq
KernelVersion: 4.14
Contact: arnaud.pouliquen@st.com
Description:
For audio purpose only.
Used by audio driver to set/get the spi input frequency.
This is mandatory if DFSDM is slave on SPI bus, to
provide information on the SPI clock frequency during runtime
Notice that the SPI frequency should be a multiple of sample
frequency to ensure the precision.
if DFSDM input is SPI master
Reading SPI clkout frequency,
error on writing
If DFSDM input is SPI Slave:
Reading returns value previously set.
Writing value before starting conversions.