Kernel-4.18.0-80.el8_ad7879

• 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
  

• interrupt-parent : the phandle for the interrupt controller
• 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:

ad7879@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>;
};

ad7879@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>;
};