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