Some LRADC channels have fixed pre-dividers so they can measure different voltages at full scale. The reference voltage allows to expose a scaling attribute through the IIO sysfs so that a user can compute the real voltage out of a measured sample value. Signed-off-by: Hector Palacios <hector.palacios@xxxxxxxx> --- Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt | 9 ++++++++- arch/arm/boot/dts/imx23.dtsi | 4 ++++ arch/arm/boot/dts/imx28.dtsi | 4 ++++ 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt index 4688205..6ec485c 100644 --- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt +++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt @@ -1,9 +1,12 @@ * Freescale i.MX28 LRADC device driver Required properties: -- compatible: Should be "fsl,imx28-lradc" +- compatible: "fsl,imx28-lradc", "fsl,imx23-lradc" - reg: Address and length of the register set for the device - interrupts: Should contain the LRADC interrupts +- fsl,vref: Reference voltage (in mV) for each LRADC channel. This is the + maximum voltage that can be measured at full scale in each channel + considering fixed pre-dividers. Optional properties: - fsl,lradc-touchscreen-wires: Number of wires used to connect the touchscreen @@ -18,4 +21,8 @@ Examples: reg = <0x80050000 0x2000>; interrupts = <10 14 15 16 17 18 19 20 21 22 23 24 25>; + fsl,vref = <1850 1850 1850 1850 + 1850 1850 1850 7400 + 1850 1850 3700 1850 + 3700 1850 1850 7400> }; diff --git a/arch/arm/boot/dts/imx23.dtsi b/arch/arm/boot/dts/imx23.dtsi index 587ceef..e212902 100644 --- a/arch/arm/boot/dts/imx23.dtsi +++ b/arch/arm/boot/dts/imx23.dtsi @@ -430,6 +430,10 @@ compatible = "fsl,imx23-lradc"; reg = <0x80050000 0x2000>; interrupts = <36 37 38 39 40 41 42 43 44>; + fsl,vref = <1850 1850 1850 1850 + 1850 1850 3700 7400 + 1850 1850 1850 1850 + 1850 1850 1850 7400>; status = "disabled"; }; diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi index 6a8acb0..c1b3724 100644 --- a/arch/arm/boot/dts/imx28.dtsi +++ b/arch/arm/boot/dts/imx28.dtsi @@ -865,6 +865,10 @@ reg = <0x80050000 0x2000>; interrupts = <10 14 15 16 17 18 19 20 21 22 23 24 25>; + fsl,vref = <1850 1850 1850 1850 + 1850 1850 1850 7400 + 1850 1850 3700 1850 + 3700 1850 1850 7400>; status = "disabled"; }; -- 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
