usb: dwc3_otg: Turn on VBUS before starting host
Currently the VBUS regulator is enabled only after initializing
the xHCI host stack, which can result in enumeration failures
for certain devices. This is likely due to VBUS having a
finite rise time when it is turned on, especially when a load
is already attached. Mitigate this by enabling VBUS first before
starting the host stack.
CRs-Fixed: 599498
Change-Id: I9785ae4682d0a2dfbcec921b869fc03550e0db82
Signed-off-by: Jack Pham <jackp@codeaurora.org>
diff --git a/drivers/usb/dwc3/dwc3_otg.c b/drivers/usb/dwc3/dwc3_otg.c
index cacd635..8a034d6 100644
--- a/drivers/usb/dwc3/dwc3_otg.c
+++ b/drivers/usb/dwc3/dwc3_otg.c
@@ -197,6 +197,14 @@
if (on) {
dev_dbg(otg->phy->dev, "%s: turn on host\n", __func__);
+ dwc3_otg_notify_host_mode(otg, on);
+ ret = regulator_enable(dotg->vbus_otg);
+ if (ret) {
+ dev_err(otg->phy->dev, "unable to enable vbus_otg\n");
+ dwc3_otg_notify_host_mode(otg, 0);
+ return ret;
+ }
+
/*
* This should be revisited for more testing post-silicon.
* In worst case we may need to disconnect the root hub
@@ -222,14 +230,8 @@
dev_err(otg->phy->dev,
"%s: failed to add XHCI pdev ret=%d\n",
__func__, ret);
- return ret;
- }
-
- dwc3_otg_notify_host_mode(otg, on);
- ret = regulator_enable(dotg->vbus_otg);
- if (ret) {
- dev_err(otg->phy->dev, "unable to enable vbus_otg\n");
- platform_device_del(dwc->xhci);
+ regulator_disable(dotg->vbus_otg);
+ dwc3_otg_notify_host_mode(otg, 0);
return ret;
}