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