Tegra SOC USB controllers
The device node for a USB controller that is part of a Tegra
SOC is as described in the document “Open Firmware Recommended
Practice : Universal Serial Bus” with the following modifications
and additions :
Required properties :
- compatible : Should be “nvidia,tegra20-ehci” for USB controllers
used in host mode. - phy_type : Should be one of “ulpi” or “utmi”.
- nvidia,vbus-gpio : If present, specifies a gpio that needs to be
activated for the bus to be powered. - nvidia,phy : phandle of the PHY instance, the controller is connected to.
Required properties for phy_type == ulpi:
- nvidia,phy-reset-gpio : The GPIO used to reset the PHY.
Optional properties:
- dr_mode : dual role mode. Indicates the working mode for
nvidia,tegra20-ehci compatible controllers. Can be “host”, “peripheral”,
or “otg”. Default to “host” if not defined for backward compatibility.
host means this is a host controller
peripheral means it is device controller
otg means it can operate as either (“on the go”) - nvidia,has-legacy-mode : boolean indicates whether this controller can
operate in legacy mode (as APX 2500 / 2600). In legacy mode some
registers are accessed through the APB_MISC base address instead of
the USB controller. Since this is a legacy issue it probably does not
warrant a compatible string of its own. - nvidia,needs-double-reset : boolean is to be set for some of the Tegra2
USB ports, which need reset twice due to hardware issues.
