blob: 58fa3e48481dee38f97e42523f0ce9eb7c2d6ec6 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
display-timing bindings
=======================
display-timings node
--------------------
required properties:
- none
optional properties:
- native-mode: The native mode for the display, in case multiple modes are
provided. When omitted, assume the first node is the native.
timing subnode
--------------
required properties:
- hactive, vactive: display resolution
- hfront-porch, hback-porch, hsync-len: horizontal display timing parameters
in pixels
vfront-porch, vback-porch, vsync-len: vertical display timing parameters in
lines
- clock-frequency: display clock in Hz
optional properties:
- hsync-active: hsync pulse is active low/high/ignored
- vsync-active: vsync pulse is active low/high/ignored
- de-active: data-enable pulse is active low/high/ignored
- pixelclk-active: with
- active high = drive pixel data on rising edge/
sample data on falling edge
- active low = drive pixel data on falling edge/
sample data on rising edge
- ignored = ignored
- syncclk-active: with
- active high = drive sync on rising edge/
sample sync on falling edge of pixel
clock
- active low = drive sync on falling edge/
sample sync on rising edge of pixel
clock
- omitted = same configuration as pixelclk-active
- interlaced (bool): boolean to enable interlaced mode
- doublescan (bool): boolean to enable doublescan mode
- doubleclk (bool): boolean to enable doubleclock mode
All the optional properties that are not bool follow the following logic:
<1>: high active
<0>: low active
omitted: not used on hardware
There are different ways of describing the capabilities of a display. The
devicetree representation corresponds to the one commonly found in datasheets
for displays. If a display supports multiple signal timings, the native-mode
can be specified.
The parameters are defined as:
+----------+-------------------------------------+----------+-------+
| | ^ | | |
| | |vback_porch | | |
| | v | | |
+----------#######################################----------+-------+
| # ^ # | |
| # | # | |
| hback # | # hfront | hsync |
| porch # | hactive # porch | len |
|<-------->#<-------+--------------------------->#<-------->|<----->|
| # | # | |
| # |vactive # | |
| # | # | |
| # v # | |
+----------#######################################----------+-------+
| | ^ | | |
| | |vfront_porch | | |
| | v | | |
+----------+-------------------------------------+----------+-------+
| | ^ | | |
| | |vsync_len | | |
| | v | | |
+----------+-------------------------------------+----------+-------+
Example:
display-timings {
native-mode = <&timing0>;
timing0: 1080p24 {
/* 1920x1080p24 */
clock-frequency = <52000000>;
hactive = <1920>;
vactive = <1080>;
hfront-porch = <25>;
hback-porch = <25>;
hsync-len = <25>;
vback-porch = <2>;
vfront-porch = <2>;
vsync-len = <2>;
hsync-active = <1>;
};
};
Every required property also supports the use of ranges, so the commonly used
datasheet description with minimum, typical and maximum values can be used.
Example:
timing1: timing {
/* 1920x1080p24 */
clock-frequency = <148500000>;
hactive = <1920>;
vactive = <1080>;
hsync-len = <0 44 60>;
hfront-porch = <80 88 95>;
hback-porch = <100 148 160>;
vfront-porch = <0 4 6>;
vback-porch = <0 36 50>;
vsync-len = <0 5 6>;
};
|
