1 /*
2  * Copyright 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>
3  *
4  * description of display timings
5  *
6  * This file is released under the GPLv2
7  */
8 
9 #ifndef __LINUX_DISPLAY_TIMING_H
10 #define __LINUX_DISPLAY_TIMING_H
11 
12 #include <linux/bitops.h>
13 #include <linux/types.h>
14 
15 enum display_flags {
16 	DISPLAY_FLAGS_HSYNC_LOW		= BIT(0),
17 	DISPLAY_FLAGS_HSYNC_HIGH	= BIT(1),
18 	DISPLAY_FLAGS_VSYNC_LOW		= BIT(2),
19 	DISPLAY_FLAGS_VSYNC_HIGH	= BIT(3),
20 
21 	/* data enable flag */
22 	DISPLAY_FLAGS_DE_LOW		= BIT(4),
23 	DISPLAY_FLAGS_DE_HIGH		= BIT(5),
24 	/* drive data on pos. edge */
25 	DISPLAY_FLAGS_PIXDATA_POSEDGE	= BIT(6),
26 	/* drive data on neg. edge */
27 	DISPLAY_FLAGS_PIXDATA_NEGEDGE	= BIT(7),
28 	DISPLAY_FLAGS_INTERLACED	= BIT(8),
29 	DISPLAY_FLAGS_DOUBLESCAN	= BIT(9),
30 	DISPLAY_FLAGS_DOUBLECLK		= BIT(10),
31 };
32 
33 /*
34  * A single signal can be specified via a range of minimal and maximal values
35  * with a typical value, that lies somewhere inbetween.
36  */
37 struct timing_entry {
38 	u32 min;
39 	u32 typ;
40 	u32 max;
41 };
42 
43 /*
44  * Single "mode" entry. This describes one set of signal timings a display can
45  * have in one setting. This struct can later be converted to struct videomode
46  * (see include/video/videomode.h). As each timing_entry can be defined as a
47  * range, one struct display_timing may become multiple struct videomodes.
48  *
49  * Example: hsync active high, vsync active low
50  *
51  *				    Active Video
52  * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
53  *	  |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
54  *	  |	     |	 porch  |		     |	 porch	 |
55  *
56  * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
57  *
58  * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
59  */
60 struct display_timing {
61 	struct timing_entry pixelclock;
62 
63 	struct timing_entry hactive;		/* hor. active video */
64 	struct timing_entry hfront_porch;	/* hor. front porch */
65 	struct timing_entry hback_porch;	/* hor. back porch */
66 	struct timing_entry hsync_len;		/* hor. sync len */
67 
68 	struct timing_entry vactive;		/* ver. active video */
69 	struct timing_entry vfront_porch;	/* ver. front porch */
70 	struct timing_entry vback_porch;	/* ver. back porch */
71 	struct timing_entry vsync_len;		/* ver. sync len */
72 
73 	enum display_flags flags;		/* display flags */
74 };
75 
76 /*
77  * This describes all timing settings a display provides.
78  * The native_mode is the default setting for this display.
79  * Drivers that can handle multiple videomodes should work with this struct and
80  * convert each entry to the desired end result.
81  */
82 struct display_timings {
83 	unsigned int num_timings;
84 	unsigned int native_mode;
85 
86 	struct display_timing **timings;
87 };
88 
89 /* get one entry from struct display_timings */
90 static inline struct display_timing *display_timings_get(const struct
91 							 display_timings *disp,
92 							 unsigned int index)
93 {
94 	if (disp->num_timings > index)
95 		return disp->timings[index];
96 	else
97 		return NULL;
98 }
99 
100 void display_timings_release(struct display_timings *disp);
101 
102 #endif
103