xref: /linux/include/video/display_timing.h (revision 75bf465f0bc33e9b776a46d6a1b9b990f5fb7c37)
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 */
display_timings_get(const struct display_timings * disp,unsigned int index)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
106