[linux-sunxi] [PATCH v3 0/5] Add dual-role OTG support for Allwinner H3

[Ondřej Jirman]

Hi Icenowy,

when I was trying to add OTG support I found an issue with powercycling.
When I have USB cable connecting PC and the OTG port on the SBC, when
the board enables the vbus, it would become impossible to power cycle
the board after poweroff. The reason being that when vbus is enabled,
the board is powered from the OTG port even if you disconnect the barrel
plug.

Should kernel turn off the vbus before shutting down/restarting? What do
you think?

regards,
  o.

Dne 6.3.2017 v 23:34 Icenowy Zheng napsal(a):
> Allwinner H3 have a its USB PHY0 routed to two USB controllers: one is
> a MUSB controller, which can work in peripheral mode, but works badly in
> host mode (several hardware will fail on the MUSB controller, even connect
> one MUSB controller in peripheral mode to another one in host mode cannot
> work); the other is a pair of EHCI/OHCI controller, which can work only
> in host mode, but have better compatibillity. The route is controlled in
> a register, which we have set it to HCI only when we do not know about
> it well.
> 
> Add support to route to the best controller according to current USB mode
> (host/peripheral).
> 
> Note: Currently even if hardware only support hostmode, we should still
> enable the MUSB controller, as it controls the USB mode. (Some this kind
> of hardware can also work in peripheral mode by settings in the sysfs
> node of MUSB, then connect it to another host via a USB Type-A to Type-A
> cable.)
> 
> Patch 1 changes the device tree binding to include the "pmu0" for HCI pair.
> 
> Patch 2 adds support for auto routing of PHY0. It's currently only enabled
> on H3, but it's easy to extend it to other SoCs which feature this
> route control.
> 
> Patch 3 adds necessary device tree nodes to the H3 DTSI file. Note: The
> phy is not bind for OHCI/EHCI0, as OHCI/EHCI drivers will keep the VBUS
> on. Only MUSB driver can properly handle a dual-role PHY.
> 
> Patch 4 enables USB OTG functionality on Orange Pi One board, which is
> the only H3 board I have that have proper OTG function. It's easy to
> enable OTG on other boards with their schematics.
> 
> Patch 5 enables USB OTG functionality on Orange Pi Zero board, as the
> board cannot output power on Vbus, I only enabled peripheral mode by
> default.
> 
> The USB PHY on V3s/A64 SoCs also feature this capability, and it will
> be soon enabled on these SoCs after this patchset is merged.
> 
> Icenowy Zheng (5):
>   dt: bindings: add pmu0 regs for USB PHYs on Allwinner H3/V3s/A64
>   phy: sun4i-usb: support automatically switch PHY0 route to MUSB/HCI
>   ARM: dts: sun8i: h3: add usb_otg and OHCI/EHCI for usbc0 on H3
>   ARM: dts: sun8i: h3: enable USB OTG on Orange Pi One
>   ARM: dts: sun8i: h2+: enable USB OTG for Orange Pi Zero board
> 
>  .../devicetree/bindings/phy/sun4i-usb-phy.txt      |  1 +
>  arch/arm/boot/dts/sun8i-h2-plus-orangepi-zero.dts  | 14 ++++++
>  arch/arm/boot/dts/sun8i-h3-orangepi-one.dts        | 22 +++++++++-
>  arch/arm/boot/dts/sun8i-h3.dtsi                    | 32 ++++++++++++++
>  drivers/phy/phy-sun4i-usb.c                        | 50 ++++++++++++++--------
>  5 files changed, 101 insertions(+), 18 deletions(-)
> 

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