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
15enum 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 */
37struct 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 */
60struct 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 */
82struct 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 */
90static 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
100void display_timings_release(struct display_timings *disp);
101
102#endif
103