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 <20190212151413.24632-9-narmstrong@baylibre.com> <CAFBinCBoahGTbnii0Dhfj75YC8u2HjodAqFWwtD=K3xOZ-wGPw@mail.gmail.com>
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From:   Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Date:   Sat, 2 Mar 2019 11:29:01 +0100
Message-ID: <CAFBinCDjFJS58+6yqxrsyHvhycsg2sC4tTtRj8O=GkcPJpR5Tg@mail.gmail.com>
Subject: Re: [PATCH 8/8] usb: dwc3: Add Amlogic G12A DWC3 glue
To:     Neil Armstrong <narmstrong@baylibre.com>
Cc:     gregkh@linuxfoundation.org, hminas@synopsys.com, balbi@kernel.org,
        kishon@ti.com, linux-amlogic@lists.infradead.org,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Neil,

> > +static int dwc3_meson_g12a_debugfs_init(struct dwc3_meson_g12a *priv)
> > +{
> > +       priv->root = debugfs_create_dir("dwc3-meson-g12a", NULL);
> > +       if (IS_ERR(priv->root))
> > +               return PTR_ERR(priv->root);
> > +
> > +       debugfs_create_file("mode_force", 0600, priv->root, priv,
> > +                           &dwc3_meson_g12a_mode_force_fops);
> > +
> > +       debugfs_create_file("otg_id", 0400, priv->root, priv,
> > +                           &dwc3_meson_g12a_otg_id_fops);
> > +
> > +       return 0;
> > +}
I just stumbled across the "USB role switch framework", see [0]
it seems to provide a userspace API as well and two in-kernel drivers
are using this framework already
(drivers/usb/gadget/udc/renesas_usb3.c,
drivers/usb/roles/intel-xhci-usb-role-switch.c)


[0] https://elixir.bootlin.com/linux/v5.0-rc8/source/drivers/usb/roles/class.c#L246