On Sun, 17 Apr 2022 at 10:45, Sergey Nazaryev <ser...@coolautomation.com> wrote:
>
> > So I think the right place to call usb_gadget_initialize is probably
> > before registering the acm gadget function into acm_stdio_start(). Can
> > you try this? and submit a follow_up fix patch if working?
>
> It's required for `usb_gadget_initialize` to provide a "USB
> controller index" as an argument. It's pretty obvious how to do it in
> "interactive world" (e.g. to ask user for this number via CLI, like
> it was in commands mentioned in my previous message) but in our case
> we need to provide this number in non-interactive manner.
>
> There is not an elegant solution with hardcoding '0' as a controller
> index like it was done in `ether` gadget [1], but it seems that it
> was a temporary fix ("This is a preparatory work for DM support for
> UDC drivers") that occasionaly became a permament solution.
>
> So, that's why I suggested to add a new subcommand to `usb` for OTG
> initialization: in my opinion, it's better to require an explicit
> call of something like `usb otgstart 0` than hardcoding a '0' into
> the code. One more option is to add a new environment variable to
> explictly specify a controller index, and read this variable from all
> places when it requires.
>
> P.S. I already put `usb_gadget_intiialize(0)` to my board code, and
> ACM gadget started working; so the remaining problem is only to
> decide where is the best place for this call.Yes, but whatever the solution, we also need to know the controller index from gadget driver, since we need it for usb_gadget_handle_interrupts(index). So an env or global variable would be at least a good start. Regards, Loic > > [1]: > https://source.denx.de/u-boot/u-boot/-/blob/master/drivers/usb/gadget/ether.c#L2355
