[lkml]   [2016]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH v8 2/3] usb: dwc2: assert phy reset when waking up in rk3288 platform
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

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

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

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

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);
jiffies + msecs_to_jiffies(71));
} else {
 \ /
  Last update: 2016-09-24 20:52    [W:0.089 / U:0.068 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site