Re: Milk-V Duo 256M: USB peripheral mode works on mainline, how should dr_mode be handled?

[Chen-Yu Yeh <chenyou910331@gmail.com>]

(Resending as plain text, the list rejected the HTML version. Sorry for
the duplicate.)

Inochi Amaoto wrote:
> In fact, neither is prefered, the right way to use dual-role switch,
> but it seems like broken. If you want to fix this, feel free to do
> that. If not, ship the dts with the behavior from vendor.

Thanks. I'll look into getting the dual-role switch working on CV18xx,
so that one DTB can do both host and peripheral.

Could you tell me what you saw broken when you tried it? From reading
the code, my guess is the PHY: with dr_mode = "otg", usb_add_hcd() sets
the PHY to host mode at probe (ID override in the top syscon), and
nothing sets it back when the role switches to device. The PHY driver
also treats OTG mode as a no-op. I'll start testing from there.

And to make sure I read you correctly: if this can't be fixed in
reasonable time, do you mean I should send a dts patch that matches
the vendor image's behavior (peripheral by default)?

Thanks,
Chen-Yu