xref: /OK3568_Linux_fs/kernel/Documentation/devicetree/bindings/iio/iio-bindings.txt (revision 4882a59341e53eb6f0b4789bf948001014eff981)

This binding is derived from clock bindings, and based on suggestions
from Lars-Peter Clausen [1].

Sources of IIO channels can be represented by any node in the device
tree. Those nodes are designated as IIO providers. IIO consumer
nodes use a phandle and IIO specifier pair to connect IIO provider
outputs to IIO inputs. Similar to the gpio specifiers, an IIO
specifier is an array of one or more cells identifying the IIO
output on a device. The length of an IIO specifier is defined by the
value of a #io-channel-cells property in the IIO provider node.

[1] https://marc.info/?l=linux-iio&m=135902119507483&w=2

==IIO providers==

Required properties:
#io-channel-cells: Number of cells in an IIO specifier; Typically 0 for nodes
		   with a single IIO output and 1 for nodes with multiple
		   IIO outputs.

Optional properties:
label:		   A symbolic name for the device.


Example for a simple configuration with no trigger:

	adc: voltage-sensor@35 {
		compatible = "maxim,max1139";
		reg = <0x35>;
		#io-channel-cells = <1>;
		label = "voltage_feedback_group1";
	};

Example for a configuration with trigger:

	adc@35 {
		compatible = "some-vendor,some-adc";
		reg = <0x35>;

		adc1: iio-device@0 {
			#io-channel-cells = <1>;
			/* other properties */
		};
		adc2: iio-device@1 {
			#io-channel-cells = <1>;
			/* other properties */
		};
	};

==IIO consumers==

Required properties:
io-channels:	List of phandle and IIO specifier pairs, one pair
		for each IIO input to the device. Note: if the
		IIO provider specifies '0' for #io-channel-cells,
		then only the phandle portion of the pair will appear.

Optional properties:
io-channel-names:
		List of IIO input name strings sorted in the same
		order as the io-channels property. Consumers drivers
		will use io-channel-names to match IIO input names
		with IIO specifiers.
io-channel-ranges:
		Empty property indicating that child nodes can inherit named
		IIO channels from this node. Useful for bus nodes to provide
		and IIO channel to their children.

For example:

	device {
		io-channels = <&adc 1>, <&ref 0>;
		io-channel-names = "vcc", "vdd";
	};

This represents a device with two IIO inputs, named "vcc" and "vdd".
The vcc channel is connected to output 1 of the &adc device, and the
vdd channel is connected to output 0 of the &ref device.

==Example==

	adc: max1139@35 {
		compatible = "maxim,max1139";
		reg = <0x35>;
		#io-channel-cells = <1>;
	};

	...

	iio-hwmon {
		compatible = "iio-hwmon";
		io-channels = <&adc 0>, <&adc 1>, <&adc 2>,
			<&adc 3>, <&adc 4>, <&adc 5>,
			<&adc 6>, <&adc 7>, <&adc 8>,
			<&adc 9>;
	};

	some_consumer {
		compatible = "some-consumer";
		io-channels = <&adc 10>, <&adc 11>;
		io-channel-names = "adc1", "adc2";
	};