xref: /freebsd/sys/contrib/device-tree/Bindings/iio/resolver/ad2s90.txt (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
1Analog Devices AD2S90 Resolver-to-Digital Converter
2
3https://www.analog.com/en/products/ad2s90.html
4
5Required properties:
6  - compatible: should be "adi,ad2s90"
7  - reg: SPI chip select number for the device
8  - spi-max-frequency: set maximum clock frequency, must be 830000
9  - spi-cpol and spi-cpha:
10        Either SPI mode (0,0) or (1,1) must be used, so specify none or both of
11        spi-cpha, spi-cpol.
12
13See for more details:
14    Documentation/devicetree/bindings/spi/spi-bus.txt
15
16Note about max frequency:
17    Chip's max frequency, as specified in its datasheet, is 2Mhz. But a 600ns
18    delay is expected between the application of a logic LO to CS and the
19    application of SCLK, as also specified. And since the delay is not
20    implemented in the spi code, to satisfy it, SCLK's period should be at most
21    2 * 600ns, so the max frequency should be 1 / (2 * 6e-7), which gives
22    roughly 830000Hz.
23
24Example:
25resolver@0 {
26	compatible = "adi,ad2s90";
27	reg = <0>;
28	spi-max-frequency = <830000>;
29	spi-cpol;
30	spi-cpha;
31};
32