From 1351b50cc4b8abcab128febf3a27d01af44697b3 Mon Sep 17 00:00:00 2001 From: Peter Rosin Date: Mon, 23 Apr 2018 23:08:06 +0200 Subject: dt-bindings: iio: afe: add binding for current-sense-shunt 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. Signed-off-by: Peter Rosin Reviewed-by: Rob Herring Signed-off-by: Jonathan Cameron --- .../bindings/iio/afe/current-sense-shunt.txt | 41 ++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt (limited to 'Documentation/devicetree/bindings/iio') 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..8e7b3e408a52 --- /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>; + }; + }; +}; -- cgit v1.2.3