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

   1 # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 %YAML 1.2
   3 ---
   4 $id: http://devicetree.org/schemas/display/panel/panel-timing.yaml#
   5 $schema: http://devicetree.org/meta-schemas/core.yaml#
   6
   7 title: panel timing bindings
   8
   9 maintainers:
  10   - Thierry Reding <thierry.reding@gmail.com>
  11   - Sam Ravnborg <sam@ravnborg.org>
  12
  13 description: |
  14   There are different ways of describing the timing data of a panel. The
  15   devicetree representation corresponds to the one commonly found in datasheets
  16   for panels.
  17
  18   The parameters are defined as seen in the following illustration.
  19
  20   +----------+-------------------------------------+----------+-------+
  21   |          |        ^                            |          |       |
  22   |          |        |vback_porch                 |          |       |
  23   |          |        v                            |          |       |
  24   +----------#######################################----------+-------+
  25   |          #        ^                            #          |       |
  26   |          #        |                            #          |       |
  27   |  hback   #        |                            #  hfront  | hsync |
  28   |   porch  #        |       hactive              #  porch   |  len  |
  29   |<-------->#<-------+--------------------------->#<-------->|<----->|
  30   |          #        |                            #          |       |
  31   |          #        |vactive                     #          |       |
  32   |          #        |                            #          |       |
  33   |          #        v                            #          |       |
  34   +----------#######################################----------+-------+
  35   |          |        ^                            |          |       |
  36   |          |        |vfront_porch                |          |       |
  37   |          |        v                            |          |       |
  38   +----------+-------------------------------------+----------+-------+
  39   |          |        ^                            |          |       |
  40   |          |        |vsync_len                   |          |       |
  41   |          |        v                            |          |       |
  42   +----------+-------------------------------------+----------+-------+
  43
  44
  45   The following is the panel timings shown with time on the x-axis.
  46   This matches the timing diagrams often found in data sheets.
  47
  48               Active                 Front           Sync           Back
  49               Region                 Porch                          Porch
  50   <-----------------------><----------------><-------------><-------------->
  51     //////////////////////|
  52    ////////////////////// |
  53   //////////////////////  |..................               ................
  54                                              _______________
  55
  56   Timing can be specified either as a typical value or as a tuple
  57   of min, typ, max values.
  58
  59 properties:
  60
  61   clock-frequency:
  62     description: Panel clock in Hz
  63
  64   hactive:
  65     $ref: /schemas/types.yaml#/definitions/uint32
  66     description: Horizontal panel resolution in pixels
  67
  68   vactive:
  69     $ref: /schemas/types.yaml#/definitions/uint32
  70     description: Vertical panel resolution in pixels
  71
  72   hfront-porch:
  73     description: Horizontal front porch panel timing
  74     $ref: /schemas/types.yaml#/definitions/uint32-array
  75     oneOf:
  76       - maxItems: 1
  77         items:
  78           description: typical number of pixels
  79       - minItems: 3
  80         maxItems: 3
  81         items:
  82           description: min, typ, max number of pixels
  83
  84   hback-porch:
  85     description: Horizontal back porch timing
  86     $ref: /schemas/types.yaml#/definitions/uint32-array
  87     oneOf:
  88       - maxItems: 1
  89         items:
  90           description: typical number of pixels
  91       - minItems: 3
  92         maxItems: 3
  93         items:
  94           description: min, typ, max number of pixels
  95
  96   hsync-len:
  97     description: Horizontal sync length panel timing
  98     $ref: /schemas/types.yaml#/definitions/uint32-array
  99     oneOf:
 100       - maxItems: 1
 101         items:
 102           description: typical number of pixels
 103       - minItems: 3
 104         maxItems: 3
 105         items:
 106           description: min, typ, max number of pixels
 107
 108   vfront-porch:
 109     description: Vertical front porch panel timing
 110     $ref: /schemas/types.yaml#/definitions/uint32-array
 111     oneOf:
 112       - maxItems: 1
 113         items:
 114           description: typical number of lines
 115       - minItems: 3
 116         maxItems: 3
 117         items:
 118           description: min, typ, max number of lines
 119
 120   vback-porch:
 121     description: Vertical back porch panel timing
 122     $ref: /schemas/types.yaml#/definitions/uint32-array
 123     oneOf:
 124       - maxItems: 1
 125         items:
 126           description: typical number of lines
 127       - minItems: 3
 128         maxItems: 3
 129         items:
 130           description: min, typ, max number of lines
 131
 132   vsync-len:
 133     description: Vertical sync length panel timing
 134     $ref: /schemas/types.yaml#/definitions/uint32-array
 135     oneOf:
 136       - maxItems: 1
 137         items:
 138           description: typical number of lines
 139       - minItems: 3
 140         maxItems: 3
 141         items:
 142           description: min, typ, max number of lines
 143
 144   hsync-active:
 145     description: |
 146       Horizontal sync pulse.
 147       0 selects active low, 1 selects active high.
 148       If omitted then it is not used by the hardware
 149     $ref: /schemas/types.yaml#/definitions/uint32
 150     enum: [0, 1]
 151
 152   vsync-active:
 153     description: |
 154       Vertical sync pulse.
 155       0 selects active low, 1 selects active high.
 156       If omitted then it is not used by the hardware
 157     $ref: /schemas/types.yaml#/definitions/uint32
 158     enum: [0, 1]
 159
 160   de-active:
 161     description: |
 162       Data enable.
 163       0 selects active low, 1 selects active high.
 164       If omitted then it is not used by the hardware
 165     $ref: /schemas/types.yaml#/definitions/uint32
 166     enum: [0, 1]
 167
 168   pixelclk-active:
 169     description: |
 170       Data driving on rising or falling edge.
 171       Use 0 to drive pixel data on falling edge and
 172       sample data on rising edge.
 173       Use 1 to drive pixel data on rising edge and
 174       sample data on falling edge
 175     $ref: /schemas/types.yaml#/definitions/uint32
 176     enum: [0, 1]
 177
 178   syncclk-active:
 179     description: |
 180       Drive sync on rising or sample sync on falling edge.
 181       If not specified then the setup is as specified by pixelclk-active.
 182       Use 0 to drive sync on falling edge and
 183       sample sync on rising edge of pixel clock.
 184       Use 1 to drive sync on rising edge and
 185       sample sync on falling edge of pixel clock
 186     $ref: /schemas/types.yaml#/definitions/uint32
 187     enum: [0, 1]
 188
 189   interlaced:
 190     type: boolean
 191     description: Enable interlaced mode
 192
 193   doublescan:
 194     type: boolean
 195     description: Enable double scan mode
 196
 197   doubleclk:
 198     type: boolean
 199     description: Enable double clock mode
 200
 201 required:
 202   - clock-frequency
 203   - hactive
 204   - vactive
 205   - hfront-porch
 206   - hback-porch
 207   - hsync-len
 208   - vfront-porch
 209   - vback-porch
 210   - vsync-len
 211
 212 additionalProperties: false
 213
 214 ...