LXR linux/include/video/display

   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/* VESA display monitor timing parameters */
  16#define VESA_DMT_HSYNC_LOW              BIT(0)
  17#define VESA_DMT_HSYNC_HIGH             BIT(1)
  18#define VESA_DMT_VSYNC_LOW              BIT(2)
  19#define VESA_DMT_VSYNC_HIGH             BIT(3)
  20
  21/* display specific flags */
  22#define DISPLAY_FLAGS_DE_LOW            BIT(0)  /* data enable flag */
  23#define DISPLAY_FLAGS_DE_HIGH           BIT(1)
  24#define DISPLAY_FLAGS_PIXDATA_POSEDGE   BIT(2)  /* drive data on pos. edge */
  25#define DISPLAY_FLAGS_PIXDATA_NEGEDGE   BIT(3)  /* drive data on neg. edge */
  26#define DISPLAY_FLAGS_INTERLACED        BIT(4)
  27#define DISPLAY_FLAGS_DOUBLESCAN        BIT(5)
  28
  29/*
  30 * A single signal can be specified via a range of minimal and maximal values
  31 * with a typical value, that lies somewhere inbetween.
  32 */
  33struct timing_entry {
  34        u32 min;
  35        u32 typ;
  36        u32 max;
  37};
  38
  39enum timing_entry_index {
  40        TE_MIN = 0,
  41        TE_TYP = 1,
  42        TE_MAX = 2,
  43};
  44
  45/*
  46 * Single "mode" entry. This describes one set of signal timings a display can
  47 * have in one setting. This struct can later be converted to struct videomode
  48 * (see include/video/videomode.h). As each timing_entry can be defined as a
  49 * range, one struct display_timing may become multiple struct videomodes.
  50 *
  51 * Example: hsync active high, vsync active low
  52 *
  53 *                                  Active Video
  54 * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
  55 *        |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
  56 *        |          |   porch  |                    |   porch   |
  57 *
  58 * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
  59 *
  60 * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
  61 */
  62struct display_timing {
  63        struct timing_entry pixelclock;
  64
  65        struct timing_entry hactive;            /* hor. active video */
  66        struct timing_entry hfront_porch;       /* hor. front porch */
  67        struct timing_entry hback_porch;        /* hor. back porch */
  68        struct timing_entry hsync_len;          /* hor. sync len */
  69
  70        struct timing_entry vactive;            /* ver. active video */
  71        struct timing_entry vfront_porch;       /* ver. front porch */
  72        struct timing_entry vback_porch;        /* ver. back porch */
  73        struct timing_entry vsync_len;          /* ver. sync len */
  74
  75        unsigned int dmt_flags;                 /* VESA DMT flags */
  76        unsigned int data_flags;                /* video data 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 value specified by index from struct timing_entry */
  93static inline u32 display_timing_get_value(const struct timing_entry *te,
  94                                           enum timing_entry_index index)
  95{
  96        switch (index) {
  97        case TE_MIN:
  98                return te->min;
  99                break;
 100        case TE_TYP:
 101                return te->typ;
 102                break;
 103        case TE_MAX:
 104                return te->max;
 105                break;
 106        default:
 107                return te->typ;
 108        }
 109}
 110
 111/* get one entry from struct display_timings */
 112static inline struct display_timing *display_timings_get(const struct
 113                                                         display_timings *disp,
 114                                                         unsigned int index)
 115{
 116        if (disp->num_timings > index)
 117                return disp->timings[index];
 118        else
 119                return NULL;
 120}
 121
 122void display_timings_release(struct display_timings *disp);
 123
 124#endif
 125