[PATCH v2 1/2] usb: dwc3: gadget: Allow runtime suspend if UDC unbinded

From: Wesley Cheng
Date: Thu Nov 05 2020 - 18:28:51 EST


The DWC3 runtime suspend routine checks for the USB connected parameter to
determine if the controller can enter into a low power state. The
connected state is only set to false after receiving a disconnect event.
However, in the case of a device initiated disconnect (i.e. UDC unbind),
the controller is halted and a disconnect event is never generated. Set
the connected flag to false if issuing a device initiated disconnect to
allow the controller to be suspended.

Signed-off-by: Wesley Cheng <wcheng@xxxxxxxxxxxxxx>
---
drivers/usb/dwc3/gadget.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 5d879b7606d5..babf977cadc0 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2012,6 +2012,17 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
}
}

+ /*
+ * Check the return value for successful resume, or error. For a
+ * successful resume, the DWC3 runtime PM resume routine will handle
+ * the run stop sequence, so avoid duplicate operations here.
+ */
+ ret = pm_runtime_get_sync(dwc->dev);
+ if (!ret || ret < 0) {
+ pm_runtime_put(dwc->dev);
+ return 0;
+ }
+
/*
* Synchronize any pending event handling before executing the controller
* halt routine.
@@ -2050,10 +2061,12 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
dwc->ev_buf->lpos = (dwc->ev_buf->lpos + count) %
dwc->ev_buf->length;
}
+ dwc->connected = false;
}

ret = dwc3_gadget_run_stop(dwc, is_on, false);
spin_unlock_irqrestore(&dwc->lock, flags);
+ pm_runtime_put(dwc->dev);

return ret;
}
--
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