An ADC is often used to measure other quantities indirectly. This binding describe one cases, a current through a shunt resistor measured by the voltage over it. Reviewed-by: Rob Herring <robh@xxxxxxxxxx> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx> --- .../bindings/iio/afe/current-sense-shunt.txt | 41 ++++++++++++++++++++++ MAINTAINERS | 6 ++++ 2 files changed, 47 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt diff --git a/Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt b/Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt new file mode 100644 index 000000000000..4d842aa85040 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt @@ -0,0 +1,41 @@ +Current Sense Shunt +=================== + +When an io-channel measures the voltage over a current sense shunt, +the interesting mesaurement is almost always the current through the +shunt, not the voltage over it. This binding describes such a current +sense circuit. + +Required properties: +- compatible : "current-sense-shunt" +- io-channels : Channel node of a voltage io-channel. +- shunt-resistor-micro-ohms : The shunt resistance in microohms. + +Example: +The system current is measured by measuring the voltage over a +3.3 ohms shunt resistor. + +sysi { + compatible = "current-sense-shunt"; + io-channels = <&tiadc 0>; + + /* Divide the voltage by 3300000/1000000 (or 3.3) for the current. */ + shunt-resistor-micro-ohms = <3300000>; +}; + +&i2c { + tiadc: adc@48 { + compatible = "ti,ads1015"; + reg = <0x48>; + #io-channel-cells = <1>; + + #address-cells = <1>; + #size-cells = <0>; + + channel@0 { /* IN0,IN1 differential */ + reg = <0>; + ti,gain = <1>; + ti,datarate = <4>; + }; + }; +}; diff --git a/MAINTAINERS b/MAINTAINERS index 36a28e979e9a..0f7bec878919 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6889,6 +6889,12 @@ F: drivers/staging/iio/ F: include/linux/iio/ F: tools/iio/ +IIO UNIT CONVERTER +M: Peter Rosin <peda@xxxxxxxxxx> +L: linux-iio@xxxxxxxxxxxxxxx +S: Maintained +F: Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt + IKANOS/ADI EAGLE ADSL USB DRIVER M: Matthieu Castet <castet.matthieu@xxxxxxx> M: Stanislaw Gruszka <stf_xl@xxxxx> -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html