Messages in this thread | | | Subject | Re: [PATCH 1/2] dt: bindings: add allwinner,otg-routed property for phy-sun4i-usb | From | Hans de Goede <> | Date | Wed, 21 Sep 2016 10:30:24 +0300 |
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Hi,
On 09/21/2016 10:19 AM, Icenowy Zheng wrote: > > > 21.09.2016, 15:10, "Hans de Goede" <hdegoede@redhat.com>: >> Hi, >> >> On 09/21/2016 10:04 AM, Icenowy Zheng wrote: >>> On some newer Allwinner SoCs (H3 or A64), the PHY0 can be either routed to >>> the MUSB controller (which is an OTG controller) or the OHCI/EHCI pair >>> (which is a Host-only controller, but more stable and easy to implement). >>> >>> This property marks whether on a certain board which controller should be >>> attached to the PHY. >>> >>> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz> >> >> Erm, I think that the idea here is to dynamically switch the routing >> based on the id-pin of the otg connector. IOW use the musb controller >> for device mode, and the ehci/ohci proper for proper host support >> when in host mode. > > At least on some boards this implementation works... > > (I mean Pine64, which has two USB-A connectors)
Right and I think it is great that you're working on this.
But even with an A connector on the board, we can still use the device mode (e.g. the SoC's native FEL mode will be used this way).
Notice that you can fake id-pin changes by echoing a mode to:
/sys/devices/platform/soc@01c00000/1c13000.usb/musb-hdrc.1.auto/mode
Valid values to echo are: host, peripheral and otg.
If you combine this with using either an USB A<->A cable, or using the port normally as a host you should be able to develop and test full otg support.
Eventually we will need a full otg support rather then your current solution and I'm afraid that your solution may get in the way of full otg support.
Regards,
Hans
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