1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/input/touchscreen/ti,am3359-tsc.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: TI AM3359 Touchscreen controller
8
9maintainers:
10  - Miquel Raynal <miquel.raynal@bootlin.com>
11
12properties:
13  compatible:
14    const: ti,am3359-tsc
15
16  ti,wires:
17    description: Wires refer to application modes i.e. 4/5/8 wire touchscreen
18      support on the platform.
19    $ref: /schemas/types.yaml#/definitions/uint32
20    enum: [4, 5, 8]
21
22  ti,x-plate-resistance:
23    description: X plate resistance
24    $ref: /schemas/types.yaml#/definitions/uint32
25
26  ti,coordinate-readouts:
27    description: The sequencer supports a total of 16 programmable steps. Each
28      step is used to read a single coordinate. A single readout is enough but
29      multiple reads can increase the quality. A value of 5 means, 5 reads for
30      X, 5 for Y and 2 for Z (always). This utilises 12 of the 16 software steps
31      available. The remaining 4 can be used by the ADC.
32    $ref: /schemas/types.yaml#/definitions/uint32
33    minimum: 1
34    maximum: 6
35
36  ti,wire-config:
37    description: Different boards could have a different order for connecting
38      wires on touchscreen. We need to provide an 8-bit number where the
39      first four bits represent the analog lines and the next 4 bits represent
40      positive/negative terminal on that input line. Notations to represent the
41      input lines and terminals respectively are as follows, AIN0 = 0, AIN1 = 1
42      and so on until AIN7 = 7. XP = 0, XN = 1, YP = 2, YN = 3.
43    $ref: /schemas/types.yaml#/definitions/uint32-array
44    minItems: 4
45    maxItems: 8
46
47  ti,charge-delay:
48    description: Length of touch screen charge delay step in terms of ADC clock
49      cycles. Charge delay value should be large in order to avoid false pen-up
50      events. This value effects the overall sampling speed, hence need to be
51      kept as low as possible, while avoiding false pen-up event. Start from a
52      lower value, say 0x400, and increase value until false pen-up events are
53      avoided. The pen-up detection happens immediately after the charge step,
54      so this does in fact function as a hardware knob for adjusting the amount
55      of "settling time".
56    $ref: /schemas/types.yaml#/definitions/uint32
57
58required:
59  - compatible
60  - ti,wires
61  - ti,x-plate-resistance
62  - ti,coordinate-readouts
63  - ti,wire-config
64
65additionalProperties: false
66
67examples:
68  - |
69    tsc {
70        compatible = "ti,am3359-tsc";
71        ti,wires = <4>;
72        ti,x-plate-resistance = <200>;
73        ti,coordinate-readouts = <5>;
74        ti,wire-config = <0x00 0x11 0x22 0x33>;
75        ti,charge-delay = <0x400>;
76    };
77