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authorArnaud Pouliquen <arnaud.pouliquen@st.com>2018-01-10 13:13:12 +0300
committerMark Brown <broonie@kernel.org>2018-01-10 13:30:13 +0300
commiteca949800d2dd761bc0c73b793e4e9ad4a997469 (patch)
treebeffb0b4fbe0a619b77ea4ad2aa401d73e5dd829 /Documentation
parente2e6771c646251657fafb2a78db566d5c2c70635 (diff)
downloadlinux-eca949800d2dd761bc0c73b793e4e9ad4a997469.tar.xz
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm3216
1 files changed, 16 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32
new file mode 100644
index 000000000000..da9822309f07
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32
@@ -0,0 +1,16 @@
+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. \ No newline at end of file