| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | Microchip AT42QT1050 Five-channel Touch Sensor IC |
| 2 | |
| 3 | The AT42QT1050 (QT1050) is a QTouchADC sensor device. The device can sense from |
| 4 | one to five keys, dependent on mode. The QT1050 includes all signal processing |
| 5 | functions necessary to provide stable sensing under a wide variety of changing |
| 6 | conditions, and the outputs are fully debounced. |
| 7 | |
| 8 | The touchkey device node should be placed inside an I2C bus node. |
| 9 | |
| 10 | Required properties: |
| 11 | - compatible: Must be "microchip,qt1050" |
| 12 | - reg: The I2C address of the device |
| 13 | - interrupts: The sink for the touchpad's IRQ output, |
| 14 | see ../interrupt-controller/interrupts.txt |
| 15 | |
| 16 | Optional properties: |
| 17 | - wakeup-source: touch keys can be used as a wakeup source |
| 18 | |
| 19 | Each button (key) is represented as a sub-node: |
| 20 | |
| 21 | Each not specified key or key with linux,code set to KEY_RESERVED gets disabled |
| 22 | in HW. |
| 23 | |
| 24 | Subnode properties: |
| 25 | - linux,code: Keycode to emit. |
| 26 | - reg: The key number. Valid values: 0, 1, 2, 3, 4. |
| 27 | |
| 28 | Optional subnode-properties: |
| 29 | |
| 30 | If a optional property is missing or has a invalid value the default value is |
| 31 | taken. |
| 32 | |
| 33 | - microchip,pre-charge-time-ns: |
| 34 | Each touchpad need some time to precharge. The value depends on the mechanical |
| 35 | layout. |
| 36 | Valid value range: 0 - 637500; values must be a multiple of 2500; |
| 37 | default is 0. |
| 38 | - microchip,average-samples: |
| 39 | Number of data samples which are averaged for each read. |
| 40 | Valid values: 1, 4, 16, 64, 256, 1024, 4096, 16384; default is 1. |
| 41 | - microchip,average-scaling: |
| 42 | The scaling factor which is used to scale the average-samples. |
| 43 | Valid values: 1, 2, 4, 8, 16, 32, 64, 128; default is 1. |
| 44 | - microchip,threshold: |
| 45 | Number of counts to register a touch detection. |
| 46 | Valid value range: 0 - 255; default is 20. |
| 47 | |
| 48 | Example: |
| 49 | QT1050 with 3 non continuous keys, key2 and key4 are disabled. |
| 50 | |
| 51 | touchkeys@41 { |
| 52 | compatible = "microchip,qt1050"; |
| 53 | reg = <0x41>; |
| 54 | interrupt-parent = <&gpio0>; |
| 55 | interrupts = <17 IRQ_TYPE_EDGE_FALLING>; |
| 56 | |
| 57 | up@0 { |
| 58 | reg = <0>; |
| 59 | linux,code = <KEY_UP>; |
| 60 | microchip,average-samples = <64>; |
| 61 | microchip,average-scaling = <16>; |
| 62 | microchip,pre-charge-time-ns = <10000>; |
| 63 | }; |
| 64 | |
| 65 | right@1 { |
| 66 | reg = <1>; |
| 67 | linux,code = <KEY_RIGHT>; |
| 68 | microchip,average-samples = <64>; |
| 69 | microchip,average-scaling = <8>; |
| 70 | }; |
| 71 | |
| 72 | down@3 { |
| 73 | reg = <3>; |
| 74 | linux,code = <KEY_DOWN>; |
| 75 | microchip,average-samples = <256>; |
| 76 | microchip,average-scaling = <16>; |
| 77 | }; |
| 78 | }; |