| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | * Analog Devices AD7879(-1)/AD7889(-1) touchscreen interface (SPI/I2C) |
| 2 | |
| 3 | Required properties: |
| 4 | - compatible : for SPI slave, use "adi,ad7879" |
| 5 | for I2C slave, use "adi,ad7879-1" |
| 6 | - reg : SPI chipselect/I2C slave address |
| 7 | See spi-bus.txt for more SPI slave properties |
| 8 | - interrupts : touch controller interrupt |
| 9 | - touchscreen-max-pressure : maximum reported pressure |
| 10 | - adi,resistance-plate-x : total resistance of X-plate (for pressure |
| 11 | calculation) |
| 12 | Optional properties: |
| 13 | - touchscreen-swapped-x-y : X and Y axis are swapped (boolean) |
| 14 | - adi,first-conversion-delay : 0-12: In 128us steps (starting with 128us) |
| 15 | 13 : 2.560ms |
| 16 | 14 : 3.584ms |
| 17 | 15 : 4.096ms |
| 18 | This property has to be a '/bits/ 8' value |
| 19 | - adi,acquisition-time : 0: 2us |
| 20 | 1: 4us |
| 21 | 2: 8us |
| 22 | 3: 16us |
| 23 | This property has to be a '/bits/ 8' value |
| 24 | - adi,median-filter-size : 0: disabled |
| 25 | 1: 4 measurements |
| 26 | 2: 8 measurements |
| 27 | 3: 16 measurements |
| 28 | This property has to be a '/bits/ 8' value |
| 29 | - adi,averaging : 0: 2 middle values (1 if median disabled) |
| 30 | 1: 4 middle values |
| 31 | 2: 8 middle values |
| 32 | 3: 16 values |
| 33 | This property has to be a '/bits/ 8' value |
| 34 | - adi,conversion-interval: : 0 : convert one time only |
| 35 | 1-255: 515us + val * 35us (up to 9.440ms) |
| 36 | This property has to be a '/bits/ 8' value |
| 37 | - gpio-controller : Switch AUX/VBAT/GPIO pin to GPIO mode |
| 38 | |
| 39 | Example: |
| 40 | |
| 41 | touchscreen0@2c { |
| 42 | compatible = "adi,ad7879-1"; |
| 43 | reg = <0x2c>; |
| 44 | interrupt-parent = <&gpio1>; |
| 45 | interrupts = <13 IRQ_TYPE_EDGE_FALLING>; |
| 46 | touchscreen-max-pressure = <4096>; |
| 47 | adi,resistance-plate-x = <120>; |
| 48 | adi,first-conversion-delay = /bits/ 8 <3>; |
| 49 | adi,acquisition-time = /bits/ 8 <1>; |
| 50 | adi,median-filter-size = /bits/ 8 <2>; |
| 51 | adi,averaging = /bits/ 8 <1>; |
| 52 | adi,conversion-interval = /bits/ 8 <255>; |
| 53 | }; |
| 54 | |
| 55 | touchscreen1@1 { |
| 56 | compatible = "adi,ad7879"; |
| 57 | spi-max-frequency = <5000000>; |
| 58 | reg = <1>; |
| 59 | spi-cpol; |
| 60 | spi-cpha; |
| 61 | gpio-controller; |
| 62 | interrupt-parent = <&gpio1>; |
| 63 | interrupts = <13 IRQ_TYPE_EDGE_FALLING>; |
| 64 | touchscreen-max-pressure = <4096>; |
| 65 | adi,resistance-plate-x = <120>; |
| 66 | adi,first-conversion-delay = /bits/ 8 <3>; |
| 67 | adi,acquisition-time = /bits/ 8 <1>; |
| 68 | adi,median-filter-size = /bits/ 8 <2>; |
| 69 | adi,averaging = /bits/ 8 <1>; |
| 70 | adi,conversion-interval = /bits/ 8 <255>; |
| 71 | }; |