1Microchip AT42QT1050 Five-channel Touch Sensor IC
2
3The AT42QT1050 (QT1050) is a QTouchADC sensor device. The device can sense from
4one to five keys, dependent on mode. The QT1050 includes all signal processing
5functions necessary to provide stable sensing under a wide variety of changing
6conditions, and the outputs are fully debounced.
7
8The touchkey device node should be placed inside an I2C bus node.
9
10Required 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
16Optional properties:
17- wakeup-source: touch keys can be used as a wakeup source
18
19Each button (key) is represented as a sub-node:
20
21Each not specified key or key with linux,code set to KEY_RESERVED gets disabled
22in HW.
23
24Subnode properties:
25- linux,code: Keycode to emit.
26- reg: The key number. Valid values: 0, 1, 2, 3, 4.
27
28Optional subnode-properties:
29
30If a optional property is missing or has a invalid value the default value is
31taken.
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
48Example:
49QT1050 with 3 non continuous keys, key2 and key4 are disabled.
50
51touchkeys@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};
79