xref: /linux/Documentation/devicetree/bindings/display/panel/panel-timing.yaml (revision c31f4aa8fed048fa70e742c4bb49bb48dc489ab3) 
1# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/display/panel/panel-timing.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: panel timing
8
9maintainers:
10  - Thierry Reding <thierry.reding@gmail.com>
11  - Sam Ravnborg <sam@ravnborg.org>
12
13description: |
14  There are different ways of describing the timing data of a panel. The
15  devicetree representation corresponds to the one commonly found in datasheets
16  for panels.
17
18  The parameters are defined as seen in the following illustration.
19
20  +-------+----------+-------------------------------------+----------+
21  |       |          |        ^                            |          |
22  |       |          |        |vsync_len                   |          |
23  |       |          |        v                            |          |
24  +-------+----------+-------------------------------------+----------+
25  |       |          |        ^                            |          |
26  |       |          |        |vback_porch                 |          |
27  |       |          |        v                            |          |
28  +-------+----------#######################################----------+
29  |       |          #        ^                            #          |
30  |       |          #        |                            #          |
31  | hsync |  hback   #        |                            #  hfront  |
32  |  len  |   porch  #        |       hactive              #  porch   |
33  |<----->|<-------->#<-------+--------------------------->#<-------->|
34  |       |          #        |                            #          |
35  |       |          #        |vactive                     #          |
36  |       |          #        |                            #          |
37  |       |          #        v                            #          |
38  +-------+----------#######################################----------+
39  |       |          |        ^                            |          |
40  |       |          |        |vfront_porch                |          |
41  |       |          |        v                            |          |
42  +-------+----------+-------------------------------------+----------+
43
44  The following is the panel timings shown with time on the x-axis.
45  This matches the timing diagrams often found in data sheets.
46
47              Active                 Front           Sync           Back
48              Region                 Porch                          Porch
49  <-----------------------><----------------><-------------><-------------->
50    //////////////////////|
51   ////////////////////// |
52  //////////////////////  |..................               ................
53                                             _______________
54
55  Timing can be specified either as a typical value or as a tuple
56  of min, typ, max values.
57
58properties:
59
60  clock-frequency:
61    description: Panel clock in Hz
62
63  hactive:
64    $ref: /schemas/types.yaml#/definitions/uint32
65    description: Horizontal panel resolution in pixels
66
67  vactive:
68    $ref: /schemas/types.yaml#/definitions/uint32
69    description: Vertical panel resolution in pixels
70
71  hfront-porch:
72    description: Horizontal front porch panel timing
73    $ref: /schemas/types.yaml#/definitions/uint32-array
74    oneOf:
75      - maxItems: 1
76        items:
77          description: typical number of pixels
78      - minItems: 3
79        maxItems: 3
80        items:
81          description: min, typ, max number of pixels
82
83  hback-porch:
84    description: Horizontal back porch timing
85    $ref: /schemas/types.yaml#/definitions/uint32-array
86    oneOf:
87      - maxItems: 1
88        items:
89          description: typical number of pixels
90      - minItems: 3
91        maxItems: 3
92        items:
93          description: min, typ, max number of pixels
94
95  hsync-len:
96    description: Horizontal sync length panel timing
97    $ref: /schemas/types.yaml#/definitions/uint32-array
98    oneOf:
99      - maxItems: 1
100        items:
101          description: typical number of pixels
102      - minItems: 3
103        maxItems: 3
104        items:
105          description: min, typ, max number of pixels
106
107  vfront-porch:
108    description: Vertical front porch panel timing
109    $ref: /schemas/types.yaml#/definitions/uint32-array
110    oneOf:
111      - maxItems: 1
112        items:
113          description: typical number of lines
114      - minItems: 3
115        maxItems: 3
116        items:
117          description: min, typ, max number of lines
118
119  vback-porch:
120    description: Vertical back porch panel timing
121    $ref: /schemas/types.yaml#/definitions/uint32-array
122    oneOf:
123      - maxItems: 1
124        items:
125          description: typical number of lines
126      - minItems: 3
127        maxItems: 3
128        items:
129          description: min, typ, max number of lines
130
131  vsync-len:
132    description: Vertical sync length panel timing
133    $ref: /schemas/types.yaml#/definitions/uint32-array
134    oneOf:
135      - maxItems: 1
136        items:
137          description: typical number of lines
138      - minItems: 3
139        maxItems: 3
140        items:
141          description: min, typ, max number of lines
142
143  hsync-active:
144    description: |
145      Horizontal sync pulse.
146      0 selects active low, 1 selects active high.
147      If omitted then it is not used by the hardware
148    $ref: /schemas/types.yaml#/definitions/uint32
149    enum: [0, 1]
150
151  vsync-active:
152    description: |
153      Vertical sync pulse.
154      0 selects active low, 1 selects active high.
155      If omitted then it is not used by the hardware
156    $ref: /schemas/types.yaml#/definitions/uint32
157    enum: [0, 1]
158
159  de-active:
160    description: |
161      Data enable.
162      0 selects active low, 1 selects active high.
163      If omitted then it is not used by the hardware
164    $ref: /schemas/types.yaml#/definitions/uint32
165    enum: [0, 1]
166
167  pixelclk-active:
168    description: |
169      Data driving on rising or falling edge.
170      Use 0 to drive pixel data on falling edge and
171      sample data on rising edge.
172      Use 1 to drive pixel data on rising edge and
173      sample data on falling edge
174    $ref: /schemas/types.yaml#/definitions/uint32
175    enum: [0, 1]
176
177  syncclk-active:
178    description: |
179      Drive sync on rising or sample sync on falling edge.
180      If not specified then the setup is as specified by pixelclk-active.
181      Use 0 to drive sync on falling edge and
182      sample sync on rising edge of pixel clock.
183      Use 1 to drive sync on rising edge and
184      sample sync on falling edge of pixel clock
185    $ref: /schemas/types.yaml#/definitions/uint32
186    enum: [0, 1]
187
188  interlaced:
189    type: boolean
190    description: Enable interlaced mode
191
192  doublescan:
193    type: boolean
194    description: Enable double scan mode
195
196  doubleclk:
197    type: boolean
198    description: Enable double clock mode
199
200required:
201  - clock-frequency
202  - hactive
203  - vactive
204  - hfront-porch
205  - hback-porch
206  - hsync-len
207  - vfront-porch
208  - vback-porch
209  - vsync-len
210
211additionalProperties: false
212
213...
214