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
 14enum 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 */
 40struct 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 */
 63struct 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 */
 85struct 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 */
 93static 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
103void display_timings_release(struct display_timings *disp);
104
105#endif