Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1# SPDX-License-Identifier: GPL-2.0
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/input/touchscreen/touchscreen.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Common touchscreen
8
9maintainers:
10 - Dmitry Torokhov <dmitry.torokhov@gmail.com>
11
12properties:
13 panel:
14 description: If this touchscreen is integrally connected to a panel, this
15 is a reference to that panel. The presence of this reference indicates
16 that the touchscreen should be power sequenced together with the panel
17 and that they may share power and/or reset signals.
18 $ref: /schemas/types.yaml#/definitions/phandle
19
20 touchscreen-min-x:
21 description: minimum x coordinate reported
22 $ref: /schemas/types.yaml#/definitions/uint32
23 default: 0
24
25 touchscreen-min-y:
26 description: minimum y coordinate reported
27 $ref: /schemas/types.yaml#/definitions/uint32
28 default: 0
29
30 touchscreen-size-x:
31 description: horizontal resolution of touchscreen (maximum x coordinate reported + 1)
32 $ref: /schemas/types.yaml#/definitions/uint32
33
34 touchscreen-size-y:
35 description: vertical resolution of touchscreen (maximum y coordinate reported + 1)
36 $ref: /schemas/types.yaml#/definitions/uint32
37
38 touchscreen-max-pressure:
39 description: maximum reported pressure (arbitrary range dependent on the controller)
40 $ref: /schemas/types.yaml#/definitions/uint32
41
42 touchscreen-min-pressure:
43 description: minimum pressure on the touchscreen to be achieved in order
44 for the touchscreen driver to report a touch event.
45 $ref: /schemas/types.yaml#/definitions/uint32
46
47 touchscreen-fuzz-x:
48 description: horizontal noise value of the absolute input device (in pixels)
49 $ref: /schemas/types.yaml#/definitions/uint32
50
51 touchscreen-fuzz-y:
52 description: vertical noise value of the absolute input device (in pixels)
53 $ref: /schemas/types.yaml#/definitions/uint32
54
55 touchscreen-fuzz-pressure:
56 description: pressure noise value of the absolute input device (arbitrary
57 range dependent on the controller)
58 $ref: /schemas/types.yaml#/definitions/uint32
59
60 touchscreen-average-samples:
61 description: Number of data samples which are averaged for each read (valid
62 values dependent on the controller)
63 $ref: /schemas/types.yaml#/definitions/uint32
64
65 touchscreen-inverted-x:
66 description: X axis is inverted
67 type: boolean
68
69 touchscreen-inverted-y:
70 description: Y axis is inverted
71 type: boolean
72
73 touchscreen-swapped-x-y:
74 description: X and Y axis are swapped
75 Swapping is done after inverting the axis
76 type: boolean
77
78 touchscreen-x-mm:
79 description: horizontal length in mm of the touchscreen
80
81 touchscreen-y-mm:
82 description: vertical length in mm of the touchscreen
83
84 touchscreen-x-plate-ohms:
85 description: Resistance of the X-plate in Ohms
86
87 touchscreen-y-plate-ohms:
88 description: Resistance of the Y-plate in Ohms
89
90 touch-overlay:
91 description: |
92 List of nodes defining segments (touch areas) on the touchscreen.
93
94 This object can be used to describe a series of segments to restrict
95 the region within touch events are reported or buttons with a specific
96 functionality.
97
98 This is of special interest if the touchscreen is shipped with a physical
99 overlay on top of it with a frame that hides some part of the original
100 touchscreen area. Printed buttons on that overlay are also a typical
101 use case.
102
103 A new touchscreen area is defined as a sub-node without a key code. If a
104 key code is defined in the sub-node, it will be interpreted as a button.
105
106 The x-origin and y-origin properties of a touchscreen area define the
107 offset of a new origin from where the touchscreen events are referenced.
108 This offset is applied to the events accordingly. The x-size and y-size
109 properties define the size of the touchscreen effective area.
110
111 The following example shows a new touchscreen area with the new origin
112 (0',0') for the touch events generated by the device.
113
114 Touchscreen (full area)
115 ┌────────────────────────────────────────┐
116 │ ┌───────────────────────────────┐ │
117 │ │ │ │
118 │ ├ y-size │ │
119 │ │ │ │
120 │ │ touchscreen area │ │
121 │ │ (no key code) │ │
122 │ │ │ │
123 │ │ x-size │ │
124 │ ┌└──────────────┴────────────────┘ │
125 │(0',0') │
126 ┌└────────────────────────────────────────┘
127 (0,0)
128
129 where (0',0') = (0+x-origin,0+y-origin)
130
131 Sub-nodes with key codes report the touch events on their surface as key
132 events instead.
133
134 The following example shows a touchscreen with a single button on it.
135
136 Touchscreen (full area)
137 ┌───────────────────────────────────┐
138 │ │
139 │ │
140 │ ┌─────────┐ │
141 │ │button 0 │ │
142 │ │KEY_POWER│ │
143 │ └─────────┘ │
144 │ │
145 │ │
146 ┌└───────────────────────────────────┘
147 (0,0)
148
149 Segments defining buttons and clipped toushcreen areas can be combined
150 as shown in the following example.
151 In that case only the events within the touchscreen area are reported
152 as touch events. Events within the button areas report their associated
153 key code. Any events outside the defined areas are ignored.
154
155 Touchscreen (full area)
156 ┌─────────┬──────────────────────────────┐
157 │ │ │
158 │ │ ┌───────────────────────┐ │
159 │ button 0│ │ │ │
160 │KEY_POWER│ │ │ │
161 │ │ │ │ │
162 ├─────────┤ │ touchscreen area │ │
163 │ │ │ (no key code) │ │
164 │ │ │ │ │
165 │ button 1│ │ │ │
166 │ KEY_INFO│ ┌└───────────────────────┘ │
167 │ │(0',0') │
168 ┌└─────────┴──────────────────────────────┘
169 (0,0)
170
171 type: object
172
173 patternProperties:
174 '^segment-':
175 type: object
176 description:
177 Each segment is represented as a sub-node.
178 properties:
179 x-origin:
180 description: horizontal origin of the node area
181 $ref: /schemas/types.yaml#/definitions/uint32
182
183 y-origin:
184 description: vertical origin of the node area
185 $ref: /schemas/types.yaml#/definitions/uint32
186
187 x-size:
188 description: horizontal resolution of the node area
189 $ref: /schemas/types.yaml#/definitions/uint32
190
191 y-size:
192 description: vertical resolution of the node area
193 $ref: /schemas/types.yaml#/definitions/uint32
194
195 label:
196 description: descriptive name of the segment
197 $ref: /schemas/types.yaml#/definitions/string
198
199 linux,code: true
200
201 required:
202 - x-origin
203 - y-origin
204 - x-size
205 - y-size
206
207 unevaluatedProperties: false
208
209 debounce-delay-us:
210 description: Minimum duration in microseconds a signal must remain stable
211 to be considered valid.
212
213dependencies:
214 touchscreen-size-x: [ touchscreen-size-y ]
215 touchscreen-size-y: [ touchscreen-size-x ]
216 touchscreen-x-mm: [ touchscreen-y-mm ]
217 touchscreen-y-mm: [ touchscreen-x-mm ]
218
219additionalProperties: true