xref: /freebsd/sys/contrib/device-tree/Bindings/iio/dac/dpot-dac.txt (revision acb1f1269c6f4ff89a0d28ba742f6687e9ef779d) 
1Bindings for DAC emulation using a digital potentiometer
2
3It is assumed that the dpot is used as a voltage divider between the
4current dpot wiper setting and the maximum resistance of the dpot. The
5divided voltage is provided by a vref regulator.
6
7                  .------.
8   .-----------.  |      |
9   | vref      |--'    .---.
10   | regulator |--.    |   |
11   '-----------'  |    | d |
12                  |    | p |
13                  |    | o |  wiper
14                  |    | t |<---------+
15                  |    |   |
16                  |    '---'       dac output voltage
17                  |      |
18                  '------+------------+
19
20Required properties:
21- compatible: Should be "dpot-dac"
22- vref-supply: The regulator supplying the voltage divider.
23- io-channels: Channel node of the dpot to be used for the voltage division.
24- io-channel-names: Should be "dpot".
25
26Example:
27
28	&i2c {
29		dpot: mcp4651-503@28 {
30			compatible = "microchip,mcp4651-503";
31			reg = <0x28>;
32			#io-channel-cells = <1>;
33		};
34	};
35
36	dac {
37		compatible = "dpot-dac";
38		vref-supply = <&reg_3v3>;
39		io-channels = <&dpot 0>;
40		io-channel-names = "dpot";
41	};
42