From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Youn Subject: Re: [PATCH v8 2/3] usb: dwc2: assert phy reset when waking up in rk3288 platform Date: Mon, 26 Sep 2016 13:50:03 -0700 Message-ID: <65475ef5-b391-c543-4ece-a9484270e20b@synopsys.com> References: <1474743019-1050-1-git-send-email-ayaka@soulik.info> <1474743019-1050-3-git-send-email-ayaka@soulik.info> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1474743019-1050-3-git-send-email-ayaka-xPW3/0Ywev/iB9QmIjCX8w@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Randy Li , "linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" Cc: "John.Youn-HKixBCOQz3hWk0Htik3J/w@public.gmane.org" , "kishon-l0cyMroinI0@public.gmane.org" , "felipe.balbi-VuQAYsv1563Yd54FQh9/CA@public.gmane.org" , "mark.rutland-5wv7dgnIgG8@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org" , "gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "randy.li-TNX95d0MmH7DzftRWevZcw@public.gmane.org" List-Id: devicetree@vger.kernel.org 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 > --- > 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 Regards, John -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html