1*8cc087a1SEmmanuel Vadot# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) 2*8cc087a1SEmmanuel Vadot%YAML 1.2 3*8cc087a1SEmmanuel Vadot--- 4*8cc087a1SEmmanuel Vadot$id: http://devicetree.org/schemas/input/touchscreen/ti,am3359-tsc.yaml# 5*8cc087a1SEmmanuel Vadot$schema: http://devicetree.org/meta-schemas/core.yaml# 6*8cc087a1SEmmanuel Vadot 7*8cc087a1SEmmanuel Vadottitle: TI AM3359 Touchscreen controller 8*8cc087a1SEmmanuel Vadot 9*8cc087a1SEmmanuel Vadotmaintainers: 10*8cc087a1SEmmanuel Vadot - Miquel Raynal <miquel.raynal@bootlin.com> 11*8cc087a1SEmmanuel Vadot 12*8cc087a1SEmmanuel Vadotproperties: 13*8cc087a1SEmmanuel Vadot compatible: 14*8cc087a1SEmmanuel Vadot const: ti,am3359-tsc 15*8cc087a1SEmmanuel Vadot 16*8cc087a1SEmmanuel Vadot ti,wires: 17*8cc087a1SEmmanuel Vadot description: Wires refer to application modes i.e. 4/5/8 wire touchscreen 18*8cc087a1SEmmanuel Vadot support on the platform. 19*8cc087a1SEmmanuel Vadot $ref: /schemas/types.yaml#/definitions/uint32 20*8cc087a1SEmmanuel Vadot enum: [4, 5, 8] 21*8cc087a1SEmmanuel Vadot 22*8cc087a1SEmmanuel Vadot ti,x-plate-resistance: 23*8cc087a1SEmmanuel Vadot description: X plate resistance 24*8cc087a1SEmmanuel Vadot $ref: /schemas/types.yaml#/definitions/uint32 25*8cc087a1SEmmanuel Vadot 26*8cc087a1SEmmanuel Vadot ti,coordinate-readouts: 27*8cc087a1SEmmanuel Vadot description: The sequencer supports a total of 16 programmable steps. Each 28*8cc087a1SEmmanuel Vadot step is used to read a single coordinate. A single readout is enough but 29*8cc087a1SEmmanuel Vadot multiple reads can increase the quality. A value of 5 means, 5 reads for 30*8cc087a1SEmmanuel Vadot X, 5 for Y and 2 for Z (always). This utilises 12 of the 16 software steps 31*8cc087a1SEmmanuel Vadot available. The remaining 4 can be used by the ADC. 32*8cc087a1SEmmanuel Vadot $ref: /schemas/types.yaml#/definitions/uint32 33*8cc087a1SEmmanuel Vadot minimum: 1 34*8cc087a1SEmmanuel Vadot maximum: 6 35*8cc087a1SEmmanuel Vadot 36*8cc087a1SEmmanuel Vadot ti,wire-config: 37*8cc087a1SEmmanuel Vadot description: Different boards could have a different order for connecting 38*8cc087a1SEmmanuel Vadot wires on touchscreen. We need to provide an 8-bit number where the 39*8cc087a1SEmmanuel Vadot first four bits represent the analog lines and the next 4 bits represent 40*8cc087a1SEmmanuel Vadot positive/negative terminal on that input line. Notations to represent the 41*8cc087a1SEmmanuel Vadot input lines and terminals respectively are as follows, AIN0 = 0, AIN1 = 1 42*8cc087a1SEmmanuel Vadot and so on until AIN7 = 7. XP = 0, XN = 1, YP = 2, YN = 3. 43*8cc087a1SEmmanuel Vadot $ref: /schemas/types.yaml#/definitions/uint32-array 44*8cc087a1SEmmanuel Vadot minItems: 4 45*8cc087a1SEmmanuel Vadot maxItems: 8 46*8cc087a1SEmmanuel Vadot 47*8cc087a1SEmmanuel Vadot ti,charge-delay: 48*8cc087a1SEmmanuel Vadot description: Length of touch screen charge delay step in terms of ADC clock 49*8cc087a1SEmmanuel Vadot cycles. Charge delay value should be large in order to avoid false pen-up 50*8cc087a1SEmmanuel Vadot events. This value effects the overall sampling speed, hence need to be 51*8cc087a1SEmmanuel Vadot kept as low as possible, while avoiding false pen-up event. Start from a 52*8cc087a1SEmmanuel Vadot lower value, say 0x400, and increase value until false pen-up events are 53*8cc087a1SEmmanuel Vadot avoided. The pen-up detection happens immediately after the charge step, 54*8cc087a1SEmmanuel Vadot so this does in fact function as a hardware knob for adjusting the amount 55*8cc087a1SEmmanuel Vadot of "settling time". 56*8cc087a1SEmmanuel Vadot $ref: /schemas/types.yaml#/definitions/uint32 57*8cc087a1SEmmanuel Vadot 58*8cc087a1SEmmanuel Vadotrequired: 59*8cc087a1SEmmanuel Vadot - compatible 60*8cc087a1SEmmanuel Vadot - ti,wires 61*8cc087a1SEmmanuel Vadot - ti,x-plate-resistance 62*8cc087a1SEmmanuel Vadot - ti,coordinate-readouts 63*8cc087a1SEmmanuel Vadot - ti,wire-config 64*8cc087a1SEmmanuel Vadot 65*8cc087a1SEmmanuel VadotadditionalProperties: false 66*8cc087a1SEmmanuel Vadot 67*8cc087a1SEmmanuel Vadotexamples: 68*8cc087a1SEmmanuel Vadot - | 69*8cc087a1SEmmanuel Vadot tsc { 70*8cc087a1SEmmanuel Vadot compatible = "ti,am3359-tsc"; 71*8cc087a1SEmmanuel Vadot ti,wires = <4>; 72*8cc087a1SEmmanuel Vadot ti,x-plate-resistance = <200>; 73*8cc087a1SEmmanuel Vadot ti,coordinate-readouts = <5>; 74*8cc087a1SEmmanuel Vadot ti,wire-config = <0x00 0x11 0x22 0x33>; 75*8cc087a1SEmmanuel Vadot ti,charge-delay = <0x400>; 76*8cc087a1SEmmanuel Vadot }; 77