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Diffstat (limited to 'Documentation/devicetree/bindings/input/touchscreen/ad7879.txt')
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1 files changed, 71 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/input/touchscreen/ad7879.txt b/Documentation/devicetree/bindings/input/touchscreen/ad7879.txt new file mode 100644 index 000000000..afa38dc06 --- /dev/null +++ b/Documentation/devicetree/bindings/input/touchscreen/ad7879.txt @@ -0,0 +1,71 @@ +* Analog Devices AD7879(-1)/AD7889(-1) touchscreen interface (SPI/I2C) + +Required properties: +- compatible : for SPI slave, use "adi,ad7879" + for I2C slave, use "adi,ad7879-1" +- reg : SPI chipselect/I2C slave address + See spi-bus.txt for more SPI slave properties +- interrupts : touch controller interrupt +- touchscreen-max-pressure : maximum reported pressure +- adi,resistance-plate-x : total resistance of X-plate (for pressure + calculation) +Optional properties: +- touchscreen-swapped-x-y : X and Y axis are swapped (boolean) +- adi,first-conversion-delay : 0-12: In 128us steps (starting with 128us) + 13 : 2.560ms + 14 : 3.584ms + 15 : 4.096ms + This property has to be a '/bits/ 8' value +- adi,acquisition-time : 0: 2us + 1: 4us + 2: 8us + 3: 16us + This property has to be a '/bits/ 8' value +- adi,median-filter-size : 0: disabled + 1: 4 measurements + 2: 8 measurements + 3: 16 measurements + This property has to be a '/bits/ 8' value +- adi,averaging : 0: 2 middle values (1 if median disabled) + 1: 4 middle values + 2: 8 middle values + 3: 16 values + This property has to be a '/bits/ 8' value +- adi,conversion-interval: : 0 : convert one time only + 1-255: 515us + val * 35us (up to 9.440ms) + This property has to be a '/bits/ 8' value +- gpio-controller : Switch AUX/VBAT/GPIO pin to GPIO mode + +Example: + + touchscreen0@2c { + compatible = "adi,ad7879-1"; + reg = <0x2c>; + interrupt-parent = <&gpio1>; + interrupts = <13 IRQ_TYPE_EDGE_FALLING>; + touchscreen-max-pressure = <4096>; + adi,resistance-plate-x = <120>; + adi,first-conversion-delay = /bits/ 8 <3>; + adi,acquisition-time = /bits/ 8 <1>; + adi,median-filter-size = /bits/ 8 <2>; + adi,averaging = /bits/ 8 <1>; + adi,conversion-interval = /bits/ 8 <255>; + }; + + touchscreen1@1 { + compatible = "adi,ad7879"; + spi-max-frequency = <5000000>; + reg = <1>; + spi-cpol; + spi-cpha; + gpio-controller; + interrupt-parent = <&gpio1>; + interrupts = <13 IRQ_TYPE_EDGE_FALLING>; + touchscreen-max-pressure = <4096>; + adi,resistance-plate-x = <120>; + adi,first-conversion-delay = /bits/ 8 <3>; + adi,acquisition-time = /bits/ 8 <1>; + adi,median-filter-size = /bits/ 8 <2>; + adi,averaging = /bits/ 8 <1>; + adi,conversion-interval = /bits/ 8 <255>; + }; |