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 enum 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 };
  31
  32 /*
  33  * A single signal can be specified via a range of minimal and maximal values
  34  * with a typical value, that lies somewhere inbetween.
  35  */
  36 struct timing_entry {
  37         u32 min;
  38         u32 typ;
  39         u32 max;
  40 };
  41
  42 /*
  43  * Single "mode" entry. This describes one set of signal timings a display can
  44  * have in one setting. This struct can later be converted to struct videomode
  45  * (see include/video/videomode.h). As each timing_entry can be defined as a
  46  * range, one struct display_timing may become multiple struct videomodes.
  47  *
  48  * Example: hsync active high, vsync active low
  49  *
  50  *                                  Active Video
  51  * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
  52  *        |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
  53  *        |          |   porch  |                    |   porch   |
  54  *
  55  * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
  56  *
  57  * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
  58  */
  59 struct display_timing {
  60         struct timing_entry pixelclock;
  61
  62         struct timing_entry hactive;            /* hor. active video */
  63         struct timing_entry hfront_porch;       /* hor. front porch */
  64         struct timing_entry hback_porch;        /* hor. back porch */
  65         struct timing_entry hsync_len;          /* hor. sync len */
  66
  67         struct timing_entry vactive;            /* ver. active video */
  68         struct timing_entry vfront_porch;       /* ver. front porch */
  69         struct timing_entry vback_porch;        /* ver. back porch */
  70         struct timing_entry vsync_len;          /* ver. sync len */
  71
  72         enum display_flags flags;               /* display flags */
  73 };
  74
  75 /*
  76  * This describes all timing settings a display provides.
  77  * The native_mode is the default setting for this display.
  78  * Drivers that can handle multiple videomodes should work with this struct and
  79  * convert each entry to the desired end result.
  80  */
  81 struct display_timings {
  82         unsigned int num_timings;
  83         unsigned int native_mode;
  84
  85         struct display_timing **timings;
  86 };
  87
  88 /* get one entry from struct display_timings */
  89 static inline struct display_timing *display_timings_get(const struct
  90                                                          display_timings *disp,
  91                                                          unsigned int index)
  92 {
  93         if (disp->num_timings > index)
  94                 return disp->timings[index];
  95         else
  96                 return NULL;
  97 }
  98
  99 void display_timings_release(struct display_timings *disp);
 100
 101 #endif