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Provide bindings and parse OF data during initialization. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
98 lines
2.6 KiB
Plaintext
98 lines
2.6 KiB
Plaintext
This binding is derived from clock bindings, and based on suggestions
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from Lars-Peter Clausen [1].
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Sources of IIO channels can be represented by any node in the device
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tree. Those nodes are designated as IIO providers. IIO consumer
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nodes use a phandle and IIO specifier pair to connect IIO provider
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outputs to IIO inputs. Similar to the gpio specifiers, an IIO
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specifier is an array of one or more cells identifying the IIO
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output on a device. The length of an IIO specifier is defined by the
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value of a #io-channel-cells property in the IIO provider node.
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[1] http://marc.info/?l=linux-iio&m=135902119507483&w=2
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==IIO providers==
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Required properties:
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#io-channel-cells: Number of cells in an IIO specifier; Typically 0 for nodes
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with a single IIO output and 1 for nodes with multiple
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IIO outputs.
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Example for a simple configuration with no trigger:
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adc: voltage-sensor@35 {
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compatible = "maxim,max1139";
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reg = <0x35>;
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#io-channel-cells = <1>;
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};
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Example for a configuration with trigger:
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adc@35 {
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compatible = "some-vendor,some-adc";
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reg = <0x35>;
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adc1: iio-device@0 {
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#io-channel-cells = <1>;
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/* other properties */
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};
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adc2: iio-device@1 {
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#io-channel-cells = <1>;
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/* other properties */
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};
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};
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==IIO consumers==
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Required properties:
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io-channels: List of phandle and IIO specifier pairs, one pair
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for each IIO input to the device. Note: if the
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IIO provider specifies '0' for #io-channel-cells,
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then only the phandle portion of the pair will appear.
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Optional properties:
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io-channel-names:
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List of IIO input name strings sorted in the same
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order as the io-channels property. Consumers drivers
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will use io-channel-names to match IIO input names
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with IIO specifiers.
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io-channel-ranges:
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Empty property indicating that child nodes can inherit named
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IIO channels from this node. Useful for bus nodes to provide
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and IIO channel to their children.
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For example:
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device {
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io-channels = <&adc 1>, <&ref 0>;
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io-channel-names = "vcc", "vdd";
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};
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This represents a device with two IIO inputs, named "vcc" and "vdd".
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The vcc channel is connected to output 1 of the &adc device, and the
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vdd channel is connected to output 0 of the &ref device.
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==Example==
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adc: max1139@35 {
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compatible = "maxim,max1139";
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reg = <0x35>;
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#io-channel-cells = <1>;
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};
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...
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iio_hwmon {
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compatible = "iio-hwmon";
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io-channels = <&adc 0>, <&adc 1>, <&adc 2>,
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<&adc 3>, <&adc 4>, <&adc 5>,
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<&adc 6>, <&adc 7>, <&adc 8>,
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<&adc 9>;
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};
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some_consumer {
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compatible = "some-consumer";
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io-channels = <&adc 10>, <&adc 11>;
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io-channel-names = "adc1", "adc2";
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};
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