Re: [PATCH v5 10/18] tegra: usb: fdt: Add additional device tree definitions for USB ports

[Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On 01/24/2012 04:21 PM, Simon Glass wrote:
> This adds clock references to the USB part of the device tree for U-Boot.
> 
> The USB timing information may vary between boards sometimes, but for
> now we hard-code it in C. This is because all current T2x boards use
> the same values, we will deal with T3x later and we first need to agree
> on the format for this timing information in the fdt and may in fact
> decide that it has no place there.

The patch below does more than what's covered by this description...

> Signed-off-by: Simon Glass <sjg-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
> ---
> Changes in v5:
> - Add dr_mode property to control host/device/otg mode
> - Add nvidia,has-legacy-mode property per review comments
> - Change device tree comment style from // to /* */
> 
>  arch/arm/dts/tegra20.dtsi |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/dts/tegra20.dtsi b/arch/arm/dts/tegra20.dtsi
> index ec75747..b2e3a40 100644
> --- a/arch/arm/dts/tegra20.dtsi
> +++ b/arch/arm/dts/tegra20.dtsi
> @@ -176,6 +176,9 @@
>  		reg = <0xc5000000 0x4000>;
>  		interrupts = < 52 >;
>  		phy_type = "utmi";
> +		clocks = <&periph_clk 22>;	/* PERIPH_ID_USBD */
> +		dr_mode = "otg";

The dr_mode value is board-specific, so should be in tegra-seaboard.dts
not tegra20.dtsi.

For example, on true Seaboard, perhaps USB3 could operate in "otg" mode
since it's an external port, whereas on Springbank, USB3 is hard-wired
to a keyboard controller, so should be marked "host" mode only.

Related, I assume that any port marked as "otg" needs to have a VBUS
GPIO defined so that it can be turned off in device mode, or is VBUS
controlled by some other mechanism in some cases? Given that, I /think/
you can't actually mark USB3 as "otg" or "device" on Seaboard since
there's no VBUS GPIO.

-- 
nvpublic