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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/input/touchscreen/ti,am3359-tsc.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: TI AM3359 Touchscreen controller
maintainers:
- Miquel Raynal <miquel.raynal@bootlin.com>
properties:
compatible:
const: ti,am3359-tsc
ti,wires:
description: Wires refer to application modes i.e. 4/5/8 wire touchscreen
support on the platform.
$ref: /schemas/types.yaml#/definitions/uint32
enum: [4, 5, 8]
ti,x-plate-resistance:
description: X plate resistance
$ref: /schemas/types.yaml#/definitions/uint32
ti,coordinate-readouts:
description: The sequencer supports a total of 16 programmable steps. Each
step is used to read a single coordinate. A single readout is enough but
multiple reads can increase the quality. A value of 5 means, 5 reads for
X, 5 for Y and 2 for Z (always). This utilises 12 of the 16 software steps
available. The remaining 4 can be used by the ADC.
$ref: /schemas/types.yaml#/definitions/uint32
minimum: 1
maximum: 6
ti,wire-config:
description: Different boards could have a different order for connecting
wires on touchscreen. We need to provide an 8-bit number where the
first four bits represent the analog lines and the next 4 bits represent
positive/negative terminal on that input line. Notations to represent the
input lines and terminals respectively are as follows, AIN0 = 0, AIN1 = 1
and so on until AIN7 = 7. XP = 0, XN = 1, YP = 2, YN = 3.
$ref: /schemas/types.yaml#/definitions/uint32-array
minItems: 4
maxItems: 8
ti,charge-delay:
description: Length of touch screen charge delay step in terms of ADC clock
cycles. Charge delay value should be large in order to avoid false pen-up
events. This value effects the overall sampling speed, hence need to be
kept as low as possible, while avoiding false pen-up event. Start from a
lower value, say 0x400, and increase value until false pen-up events are
avoided. The pen-up detection happens immediately after the charge step,
so this does in fact function as a hardware knob for adjusting the amount
of "settling time".
$ref: /schemas/types.yaml#/definitions/uint32
required:
- compatible
- ti,wires
- ti,x-plate-resistance
- ti,coordinate-readouts
- ti,wire-config
additionalProperties: false
examples:
- |
tsc {
compatible = "ti,am3359-tsc";
ti,wires = <4>;
ti,x-plate-resistance = <200>;
ti,coordinate-readouts = <5>;
ti,wire-config = <0x00 0x11 0x22 0x33>;
ti,charge-delay = <0x400>;
};
|
