linux/Documentation/devicetree/bindings/input/input-reset.txt
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   1Input: sysrq reset sequence
   2
   3A simple binding to represent a set of keys as described in
   4include/uapi/linux/input.h. This is to communicate a sequence of keys to the
   5sysrq driver. Upon holding the keys for a specified amount of time (if
   6specified) the system is sync'ed and reset.
   7
   8Key sequences are global to the system but all the keys in a set must be coming
   9from the same input device.
  10
  11The /chosen node should contain a 'linux,sysrq-reset-seq' child node to define
  12a set of keys.
  13
  14Required property:
  15keyset: array of Linux keycodes, one keycode per cell.
  16
  17Optional property:
  18timeout-ms: duration keys must be pressed together in milliseconds before
  19generating a sysrq. If omitted the system is rebooted immediately when a valid
  20sequence has been recognized.
  21
  22Example:
  23
  24 chosen {
  25                linux,sysrq-reset-seq {
  26                        keyset = <0x03
  27                                  0x04
  28                                  0x0a>;
  29                        timeout-ms = <3000>;
  30                };
  31         };
  32
  33Would represent KEY_2, KEY_3 and KEY_9.
  34