linux/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
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   1Tegra SOC USB controllers
   2
   3The device node for a USB controller that is part of a Tegra
   4SOC is as described in the document "Open Firmware Recommended
   5Practice : Universal Serial Bus" with the following modifications
   6and additions :
   7
   8Required properties :
   9 - compatible : Should be "nvidia,tegra20-ehci" for USB controllers
  10   used in host mode.
  11 - phy_type : Should be one of "ulpi" or "utmi".
  12 - nvidia,vbus-gpio : If present, specifies a gpio that needs to be
  13   activated for the bus to be powered.
  14 - nvidia,phy : phandle of the PHY instance, the controller is connected to.
  15
  16Required properties for phy_type == ulpi:
  17  - nvidia,phy-reset-gpio : The GPIO used to reset the PHY.
  18
  19Optional properties:
  20  - dr_mode : dual role mode. Indicates the working mode for
  21   nvidia,tegra20-ehci compatible controllers.  Can be "host", "peripheral",
  22   or "otg".  Default to "host" if not defined for backward compatibility.
  23      host means this is a host controller
  24      peripheral means it is device controller
  25      otg means it can operate as either ("on the go")
  26  - nvidia,has-legacy-mode : boolean indicates whether this controller can
  27    operate in legacy mode (as APX 2500 / 2600). In legacy mode some
  28    registers are accessed through the APB_MISC base address instead of
  29    the USB controller. Since this is a legacy issue it probably does not
  30    warrant a compatible string of its own.
  31  - nvidia,needs-double-reset : boolean is to be set for some of the Tegra2
  32    USB ports, which need reset twice due to hardware issues.
  33