xref: /OK3568_Linux_fs/kernel/Documentation/ABI/testing/sysfs-bus-iio-dfsdm-adc-stm32 (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunWhat:		/sys/bus/iio/devices/iio:deviceX/in_voltage_spi_clk_freq
2*4882a593SmuzhiyunKernelVersion:	4.14
3*4882a593SmuzhiyunContact:	arnaud.pouliquen@st.com
4*4882a593SmuzhiyunDescription:
5*4882a593Smuzhiyun		For audio purpose only.
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun		Used by audio driver to set/get the spi input frequency.
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun		This is mandatory if DFSDM is slave on SPI bus, to
10*4882a593Smuzhiyun		provide information on the SPI clock frequency during runtime
11*4882a593Smuzhiyun		Notice that the SPI frequency should be a multiple of sample
12*4882a593Smuzhiyun		frequency to ensure the precision.
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun		if DFSDM input is SPI master:
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun			Reading  SPI clkout frequency,
17*4882a593Smuzhiyun			error on writing
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun		If DFSDM input is SPI Slave:
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun			Reading returns value previously set.
22*4882a593Smuzhiyun			Writing value before starting conversions.
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