> Hey Linux USBer's,
>
> I'm looking to add host support to the qualcomm OTG USB driver. The
> driver in mainline currently has gadget support only. I'm starting with
> an out-of-tree driver that has full gadget and host support. It has it's
> own OTG state machine implement in the driver, that I was about to
> forward-port to top-of-tree.
>
> However, I found the files /usb/common/usb-otg-fsm.c and I'm wondering
> what the status of that is. There appears to be only one driver
> currently using it. Should I modify the qualcomm driver
> (drivers/usb/phy/phy-msm-usb.c to use that state machine, or just try to
> mainline the state machine from the out-of-tree driver? I'm suspecting
> the former will be more work, but I want to do the right thing.
>
Hi Tim,
The OTG FSM at /usb/common/usb-otg-fsm.c is a software OTG FSM implementation
which follows On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification
(Revision 2.0 version 1.1a) Chapter 7 State Diagrams.
If the platform doesn't support hardware otg fsm, it should follow above fsm implementation since
it follows the newest OTG & EH spec. Besides, as far as I know, the qualcomm uses
chipidea core for its usb2, then it should be easy for qualcomm using this common
otg fsm implementation.
Peter
> Really I'm just checking that using the generic state machine is the
> preferred method of supporting USB OTG drivers going forward.
>
> Thanks!
>
> -- Tim Bird
> Senior Software Engineer, Sony Mobile
> Architecture Group Chair, CE Workgroup, Linux Foundation
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