77 lines
2.7 KiB
YAML
77 lines
2.7 KiB
YAML
|
# 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>;
|
||
|
|
};
|