| * 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>; |
| }; |
