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    SubjectRe: [PATCH v8 2/3] usb: dwc2: assert phy reset when waking up in rk3288 platform
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    On 9/24/2016 11:51 AM, Randy Li wrote:
    > On the rk3288 USB host-only port (the one that's not the OTG-enabled
    > port) the PHY can get into a bad state when a wakeup is asserted (not
    > just a wakeup from full system suspend but also a wakeup from
    > autosuspend).
    >
    > We can get the PHY out of its bad state by asserting its "port reset",
    > but unfortunately that seems to assert a reset onto the USB bus so it
    > could confuse things if we don't actually deenumerate / reenumerate the
    > device.
    >
    > We can also get the PHY out of its bad state by fully resetting it using
    > the reset from the CRU (clock reset unit) in chip, which does a more full
    > reset. The CRU-based reset appears to actually cause devices on the bus
    > to be removed and reinserted, which fixes the problem (albeit in a hacky
    > way).
    >
    > It's unfortunate that we need to do a full re-enumeration of devices at
    > wakeup time, but this is better than alternative of letting the bus get
    > wedged.
    >
    > Signed-off-by: Randy Li <ayaka@soulik.info>
    > ---
    > drivers/usb/dwc2/core_intr.c | 11 +++++++++++
    > 1 file changed, 11 insertions(+)
    >
    > diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
    > index d85c5c9..af27edc 100644
    > --- a/drivers/usb/dwc2/core_intr.c
    > +++ b/drivers/usb/dwc2/core_intr.c
    > @@ -345,6 +345,7 @@ static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg)
    > static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
    > {
    > int ret;
    > + struct device_node *np = hsotg->dev->of_node;
    >
    > /* Clear interrupt */
    > dwc2_writel(GINTSTS_WKUPINT, hsotg->regs + GINTSTS);
    > @@ -379,6 +380,16 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
    > /* Restart the Phy Clock */
    > pcgcctl &= ~PCGCTL_STOPPCLK;
    > dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
    > +
    > + /*
    > + * It is a quirk in Rockchip RK3288, causing by
    > + * a hardware bug. This will propagate out and
    > + * eventually we'll re-enumerate the device.
    > + * Not great but the best we can do.
    > + */
    > + if (of_device_is_compatible(np, "rockchip,rk3288-usb"))
    > + phy_reset(hsotg->phy);
    > +
    > mod_timer(&hsotg->wkp_timer,
    > jiffies + msecs_to_jiffies(71));
    > } else {
    >


    Acked-by: John Youn <johnyoun@synopsys.com>

    Regards,
    John

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