1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>
4 *
5 * description of display timings
6 */
7
8 #ifndef __LINUX_DISPLAY_TIMING_H
9 #define __LINUX_DISPLAY_TIMING_H
10
11 #include <linux/bitops.h>
12 #include <linux/types.h>
13
14 enum display_flags {
15 DISPLAY_FLAGS_HSYNC_LOW = BIT(0),
16 DISPLAY_FLAGS_HSYNC_HIGH = BIT(1),
17 DISPLAY_FLAGS_VSYNC_LOW = BIT(2),
18 DISPLAY_FLAGS_VSYNC_HIGH = BIT(3),
19
20 /* data enable flag */
21 DISPLAY_FLAGS_DE_LOW = BIT(4),
22 DISPLAY_FLAGS_DE_HIGH = BIT(5),
23 /* drive data on pos. edge */
24 DISPLAY_FLAGS_PIXDATA_POSEDGE = BIT(6),
25 /* drive data on neg. edge */
26 DISPLAY_FLAGS_PIXDATA_NEGEDGE = BIT(7),
27 DISPLAY_FLAGS_INTERLACED = BIT(8),
28 DISPLAY_FLAGS_DOUBLESCAN = BIT(9),
29 DISPLAY_FLAGS_DOUBLECLK = BIT(10),
30 /* drive sync on pos. edge */
31 DISPLAY_FLAGS_SYNC_POSEDGE = BIT(11),
32 /* drive sync on neg. edge */
33 DISPLAY_FLAGS_SYNC_NEGEDGE = BIT(12),
34 };
35
36 /*
37 * A single signal can be specified via a range of minimal and maximal values
38 * with a typical value, that lies somewhere inbetween.
39 */
40 struct timing_entry {
41 u32 min;
42 u32 typ;
43 u32 max;
44 };
45
46 /*
47 * Single "mode" entry. This describes one set of signal timings a display can
48 * have in one setting. This struct can later be converted to struct videomode
49 * (see include/video/videomode.h). As each timing_entry can be defined as a
50 * range, one struct display_timing may become multiple struct videomodes.
51 *
52 * Example: hsync active high, vsync active low
53 *
54 * Active Video
55 * Video ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
56 * |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
57 * | | porch | | porch |
58 *
59 * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
60 *
61 * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
62 */
63 struct display_timing {
64 struct timing_entry pixelclock;
65
66 struct timing_entry hactive; /* hor. active video */
67 struct timing_entry hfront_porch; /* hor. front porch */
68 struct timing_entry hback_porch; /* hor. back porch */
69 struct timing_entry hsync_len; /* hor. sync len */
70
71 struct timing_entry vactive; /* ver. active video */
72 struct timing_entry vfront_porch; /* ver. front porch */
73 struct timing_entry vback_porch; /* ver. back porch */
74 struct timing_entry vsync_len; /* ver. sync len */
75
76 enum display_flags flags; /* display flags */
77 };
78
79 /*
80 * This describes all timing settings a display provides.
81 * The native_mode is the default setting for this display.
82 * Drivers that can handle multiple videomodes should work with this struct and
83 * convert each entry to the desired end result.
84 */
85 struct display_timings {
86 unsigned int num_timings;
87 unsigned int native_mode;
88
89 struct display_timing **timings;
90 };
91
92 /* get one entry from struct display_timings */
93 static inline struct display_timing *display_timings_get(const struct
94 display_timings *disp,
95 unsigned int index)
96 {
97 if (disp->num_timings > index)
98 return disp->timings[index];
99 else
100 return NULL;
101 }
102
103 void display_timings_release(struct display_timings *disp);
104
105 #endif