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Commit c40cf770 authored by Douglas Anderson's avatar Douglas Anderson Committed by Felipe Balbi
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usb: dwc2: optionally assert phy reset when waking up


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), 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: default avatarDouglas Anderson <dianders@chromium.org>
Signed-off-by: default avatarYunzhi Li <lyz@rock-chips.com>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent cc389eaa
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