Documentation/devicetree/bindings/display/panel/display-timing.txt

   1 display-timing bindings
   2 =======================
   3
   4 display-timings node
   5 --------------------
   6
   7 required properties:
   8  - none
   9
  10 optional properties:
  11  - native-mode: The native mode for the display, in case multiple modes are
  12                 provided. When omitted, assume the first node is the native.
  13
  14 timing subnode
  15 --------------
  16
  17 required properties:
  18  - hactive, vactive: display resolution
  19  - hfront-porch, hback-porch, hsync-len: horizontal display timing parameters
  20    in pixels
  21    vfront-porch, vback-porch, vsync-len: vertical display timing parameters in
  22    lines
  23  - clock-frequency: display clock in Hz
  24
  25 optional properties:
  26  - hsync-active: hsync pulse is active low/high/ignored
  27  - vsync-active: vsync pulse is active low/high/ignored
  28  - de-active: data-enable pulse is active low/high/ignored
  29  - pixelclk-active: with
  30                         - active high = drive pixel data on rising edge/
  31                                         sample data on falling edge
  32                         - active low  = drive pixel data on falling edge/
  33                                         sample data on rising edge
  34                         - ignored     = ignored
  35  - syncclk-active: with
  36                         - active high = drive sync on rising edge/
  37                                         sample sync on falling edge of pixel
  38                                         clock
  39                         - active low  = drive sync on falling edge/
  40                                         sample sync on rising edge of pixel
  41                                         clock
  42                         - omitted     = same configuration as pixelclk-active
  43  - interlaced (bool): boolean to enable interlaced mode
  44  - doublescan (bool): boolean to enable doublescan mode
  45  - doubleclk (bool): boolean to enable doubleclock mode
  46
  47 All the optional properties that are not bool follow the following logic:
  48     <1>: high active
  49     <0>: low active
  50     omitted: not used on hardware
  51
  52 There are different ways of describing the capabilities of a display. The
  53 devicetree representation corresponds to the one commonly found in datasheets
  54 for displays. If a display supports multiple signal timings, the native-mode
  55 can be specified.
  56
  57 The parameters are defined as:
  58
  59   +----------+-------------------------------------+----------+-------+
  60   |          |        ^                            |          |       |
  61   |          |        |vback_porch                 |          |       |
  62   |          |        v                            |          |       |
  63   +----------#######################################----------+-------+
  64   |          #        ^                            #          |       |
  65   |          #        |                            #          |       |
  66   |  hback   #        |                            #  hfront  | hsync |
  67   |   porch  #        |       hactive              #  porch   |  len  |
  68   |<-------->#<-------+--------------------------->#<-------->|<----->|
  69   |          #        |                            #          |       |
  70   |          #        |vactive                     #          |       |
  71   |          #        |                            #          |       |
  72   |          #        v                            #          |       |
  73   +----------#######################################----------+-------+
  74   |          |        ^                            |          |       |
  75   |          |        |vfront_porch                |          |       |
  76   |          |        v                            |          |       |
  77   +----------+-------------------------------------+----------+-------+
  78   |          |        ^                            |          |       |
  79   |          |        |vsync_len                   |          |       |
  80   |          |        v                            |          |       |
  81   +----------+-------------------------------------+----------+-------+
  82
  83 Note: In addition to being used as subnode(s) of display-timings, the timing
  84       subnode may also be used on its own. This is appropriate if only one mode
  85       need be conveyed. In this case, the node should be named 'panel-timing'.
  86
  87
  88 Example:
  89
  90         display-timings {
  91                 native-mode = <&timing0>;
  92                 timing0: 1080p24 {
  93                         /* 1920x1080p24 */
  94                         clock-frequency = <52000000>;
  95                         hactive = <1920>;
  96                         vactive = <1080>;
  97                         hfront-porch = <25>;
  98                         hback-porch = <25>;
  99                         hsync-len = <25>;
 100                         vback-porch = <2>;
 101                         vfront-porch = <2>;
 102                         vsync-len = <2>;
 103                         hsync-active = <1>;
 104                 };
 105         };
 106
 107 Every required property also supports the use of ranges, so the commonly used
 108 datasheet description with minimum, typical and maximum values can be used.
 109
 110 Example:
 111
 112         timing1: timing {
 113                 /* 1920x1080p24 */
 114                 clock-frequency = <148500000>;
 115                 hactive = <1920>;
 116                 vactive = <1080>;
 117                 hsync-len = <0 44 60>;
 118                 hfront-porch = <80 88 95>;
 119                 hback-porch = <100 148 160>;
 120                 vfront-porch = <0 4 6>;
 121                 vback-porch = <0 36 50>;
 122                 vsync-len = <0 5 6>;
 123         };