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From:   Daniel Palmer <daniel@0x0f.com>
Date:   Thu, 6 May 2021 18:02:18 +0900
Message-ID: <CAFr9PX=qskO+vxUiNaq5e0E7BFGGuK4xzh2sM2dEO2tEtucMtA@mail.gmail.com>
Subject: Re: gemini: sl3516: Mainlining of NS 2502
To:     Linus Walleij <linus.walleij@linaro.org>
Cc:     Corentin Labbe <clabbe.montjoie@gmail.com>,
        Hans Ulli Kroll <ulli.kroll@googlemail.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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Hi Linus, Coretin

On Thu, 6 May 2021 at 08:56, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Wed, May 5, 2021 at 9:26 PM Corentin Labbe <clabbe.montjoie@gmail.com> wrote:
>
> > It seems that USB is still a bit buggy, device are detected only if plugged before boot.
>
> Yeah :/ I don't know that driver very well, only that others use it too
> so there might be some people who can help. I haven't mainlined
> that patch because there is something that seems wrong about it
> but I'm not a USB guy.

Assuming I didn't read the wrong dts this machine is using the Faraday FOTG210.
FWIW the MStar/Sigmastar ARMv7 (and earlier I think) chips use
basically the same IP for USB host (FUSBH200).
There used to be a distinct driver for the host-only version but it
got removed at some point so I added support for it to the otg driver
in my tree and it sort of works.

It seems very picky about devices being hot plugged and doesn't seem
able to enumerate low speed/full speed devices at all.
Maybe we are seeing the same issues? I have a USB bus analyzer and I
intend to debug this at some point.
Adding support for USB on the MStar stuff is pretty far off but maybe
if I find something Coretin can test to see if it helps out there too.

Thanks,

Daniel