brcm-bca Small Form Factor (SFF), Small Form-factor Pluggable (SFP), eXtensible
  Form-factor Transceiver driver
===============================================================================

Device node label must be "xfp_sfp" in order for bcm-i2c-legacy driver to assign
Transceiver to WAN interface.

Required properties:

- compatible: must be one of
  "brcm,sff" for soldered down SFF modules
  "brcm,sfp" for SFP/XFP modules, same as above, but uses MOD-DEF0 gpio for
    polling Transceiver presence

- i2c-bus: phandle, I2C bus controller for the SFP


Optional properties:

- mod-def0-gpio: GPIO phandle and a specifier of the MOD-DEF0 (AKA Mod_ABS)
  module presence input gpio signal, active (module absent) high. Must
  not be present for SFF modules
  Legacy: bp_usExtIntrOpticalModulePresence

  or:

  mod-def0: brcm,bca-extintr, external interrupt descriptor for the above gpio

  or:

  <none>: I2C polling will be used to detect if Transceiver is in connected.

- los-gpio: GPIO phandle and a specifier of the Receiver Loss of Signal
  Indication input gpio signal, active (signal lost) high
  Legacy: bp_usGpioWanSignalDetected

- tx-disable-gpio: GPIO phandle and a specifier of the Transmitter Disable
  output gpio signal, active (Tx disabled) high
  * Sometimes this pin is connected to SERDES LBE

- tx-power-gpio: GPIO phandle and a specifier of the Transmitter Tx-Power
  output gpio signal, active (Tx powered) high
  Legacy: bp_usGpioPonTxEn

- tx-power-down-gpio: GPIO phandle and specifier for the Transmitter Tx
  power down, used to disable the Tx in some Trx (commonly pin-9), active
  (Powered on) high
  Legacy: bp_usGpioOpticalModuleTxPwrDown

- tx-sd pinctrl: a pinctrl selection (pinctrl-names) named "tx-sd" must be
  set for configuring Transmitter Tx-SD signal (commonly pin 7); used for
  Rogue Tx in some TDMA optical Trx (Powered on) high