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