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 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 ``` ``````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>; }; }; ``````