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
15Required properties for phy_type == ulpi:
16  - nvidia,phy-reset-gpio : The GPIO used to reset the PHY.
17
18Optional properties:
19  - dr_mode : dual role mode. Indicates the working mode for
20   nvidia,tegra20-ehci compatible controllers.  Can be "host", "peripheral",
21   or "otg".  Default to "host" if not defined for backward compatibility.
22      host means this is a host controller
23      peripheral means it is device controller
24      otg means it can operate as either ("on the go")
25  - nvidia,has-legacy-mode : boolean indicates whether this controller can
26    operate in legacy mode (as APX 2500 / 2600). In legacy mode some
27    registers are accessed through the APB_MISC base address instead of
28    the USB controller. Since this is a legacy issue it probably does not
29    warrant a compatible string of its own.
30  - nvidia,needs-double-reset : boolean is to be set for some of the Tegra2
31    USB ports, which need reset twice due to hardware issues.
32