linux/include/video/display_timing.h
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   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