Documentation/devicetree/bindings/input/matrix-keymap.txt

   1 A simple common binding for matrix-connected key boards. Currently targeted at
   2 defining the keys in the scope of linux key codes since that is a stable and
   3 standardized interface at this time.
   4
   5 Required properties:
   6 - linux,keymap: an array of packed 1-cell entries containing the equivalent
   7   of row, column and linux key-code. The 32-bit big endian cell is packed
   8   as:
   9         row << 24 | column << 16 | key-code
  10
  11 Optional properties:
  12 Properties for the number of rows and columns are optional because some
  13 drivers will use fixed values for these.
  14 - keypad,num-rows: Number of row lines connected to the keypad controller.
  15 - keypad,num-columns: Number of column lines connected to the keypad
  16   controller.
  17
  18 Some users of this binding might choose to specify secondary keymaps for
  19 cases where there is a modifier key such as a Fn key. Proposed names
  20 for said properties are "linux,fn-keymap" or with another descriptive
  21 word for the modifier other from "Fn".
  22
  23 Example:
  24         linux,keymap = < 0x00030012
  25                          0x0102003a >;
  26         keypad,num-rows = <2>;
  27         keypad,num-columns = <8>;