include/video/display_timing.h

   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  */
  33 struct timing_entry {
  34         u32 min;
  35         u32 typ;
  36         u32 max;
  37 };
  38
  39 enum 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  */
  62 struct 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  */
  85 struct 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 */
  93 static 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 */
 112 static 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
 122 void display_timings_release(struct display_timings *disp);
 123
 124 #endif