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 	/* drive sync on pos. edge */
32 	DISPLAY_FLAGS_SYNC_POSEDGE	= BIT(11),
33 	/* drive sync on neg. edge */
34 	DISPLAY_FLAGS_SYNC_NEGEDGE	= BIT(12),
35 };
36 
37 /*
38  * A single signal can be specified via a range of minimal and maximal values
39  * with a typical value, that lies somewhere inbetween.
40  */
41 struct timing_entry {
42 	u32 min;
43 	u32 typ;
44 	u32 max;
45 };
46 
47 /*
48  * Single "mode" entry. This describes one set of signal timings a display can
49  * have in one setting. This struct can later be converted to struct videomode
50  * (see include/video/videomode.h). As each timing_entry can be defined as a
51  * range, one struct display_timing may become multiple struct videomodes.
52  *
53  * Example: hsync active high, vsync active low
54  *
55  *				    Active Video
56  * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
57  *	  |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
58  *	  |	     |	 porch  |		     |	 porch	 |
59  *
60  * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
61  *
62  * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
63  */
64 struct display_timing {
65 	struct timing_entry pixelclock;
66 
67 	struct timing_entry hactive;		/* hor. active video */
68 	struct timing_entry hfront_porch;	/* hor. front porch */
69 	struct timing_entry hback_porch;	/* hor. back porch */
70 	struct timing_entry hsync_len;		/* hor. sync len */
71 
72 	struct timing_entry vactive;		/* ver. active video */
73 	struct timing_entry vfront_porch;	/* ver. front porch */
74 	struct timing_entry vback_porch;	/* ver. back porch */
75 	struct timing_entry vsync_len;		/* ver. sync len */
76 
77 	enum display_flags flags;		/* display flags */
78 };
79 
80 /*
81  * This describes all timing settings a display provides.
82  * The native_mode is the default setting for this display.
83  * Drivers that can handle multiple videomodes should work with this struct and
84  * convert each entry to the desired end result.
85  */
86 struct display_timings {
87 	unsigned int num_timings;
88 	unsigned int native_mode;
89 
90 	struct display_timing **timings;
91 };
92 
93 /* get one entry from struct display_timings */
94 static inline struct display_timing *display_timings_get(const struct
95 							 display_timings *disp,
96 							 unsigned int index)
97 {
98 	if (disp->num_timings > index)
99 		return disp->timings[index];
100 	else
101 		return NULL;
102 }
103 
104 void display_timings_release(struct display_timings *disp);
105 
106 #endif
107