linux/Documentation/devicetree/bindings/usb/tegra-usb.txt
Simon Glass d5dfcc91b1 arm: tegra: dts: Support host/device selection and legacy mode
Some USB ports can support host and device operation. We add the dr_mode
property (as found in Freescale) for this.

One USB port has a 'legacy mode', left over from the days of pre-Tegra
chips. I don't believe this is actually used, except that we must know
to turn this off in the driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Olof Johansson <olof@lixom.net>
2012-03-07 14:36:44 -08:00

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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.
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.