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Commit ff915802 authored by Peter Rosin's avatar Peter Rosin Committed by Jonathan Cameron
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dt-bindings: iio: afe: add binding for voltage-divider 



An ADC is often used to measure other quantities indirectly. This
binding describe one cases, a "big" voltage measured with the help
of a voltage divider.

Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 1351b50c

Documentation/devicetree/bindings/iio/afe/voltage-divider.txt

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Voltage divider

===============



When an io-channel measures the midpoint of a voltage divider, the

interesting voltage is often the voltage over the full resistance

of the divider. This binding describes the voltage divider in such

a curcuit.



    Vin ----.

            |

         .-----.

         |  R  |

         '-----'

            |

            +---- Vout

            |

         .-----.

         | Rout|

         '-----'

            |

           GND



Required properties:

- compatible : "voltage-divider"

- io-channels : Channel node of a voltage io-channel measuring Vout.

- output-ohms : Resistance Rout over which the output voltage is measured.

	        See full-ohms.

- full-ohms : Resistance R + Rout for the full divider. The io-channel

	      is scaled by the Rout / (R + Rout) quotient.



Example:

The system voltage is circa 12V, but divided down with a 22/222

voltage divider (R = 200 Ohms, Rout = 22 Ohms) and fed to an ADC.



sysv {

	compatible = "voltage-divider";

	io-channels = <&maxadc 1>;



	/* Scale the system voltage by 22/222 to fit the ADC range. */

	output-ohms = <22>;

	full-ohms = <222>; /* 200 + 22 */

};



&spi {

	maxadc: adc@0 {

		compatible = "maxim,max1027";

		reg = <0>;

		#io-channel-cells = <1>;

		interrupt-parent = <&gpio5>;

		interrupts = <15 IRQ_TYPE_EDGE_RISING>;

		spi-max-frequency = <1000000>;

	};

};

MAINTAINERS

+1 −0
Original line number Original line Diff line number Diff line
@@ -6903,6 +6903,7 @@ M: Peter Rosin <peda@axentia.se> 
L:	linux-iio@vger.kernel.org

L:	linux-iio@vger.kernel.org

S:	Maintained

S:	Maintained

F:	Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt

F:	Documentation/devicetree/bindings/iio/afe/current-sense-shunt.txt

F:	Documentation/devicetree/bindings/iio/afe/voltage-divider.txt





IKANOS/ADI EAGLE ADSL USB DRIVER

IKANOS/ADI EAGLE ADSL USB DRIVER

M:	Matthieu Castet <castet.matthieu@free.fr>

M:	Matthieu Castet <castet.matthieu@free.fr>