usb: dwc3: gadget: prevent DCTL register corruption

If we don't read out the contents of the register
(in order to reinitialize 'reg' variable) we will
be writing unknown contents to the DCTL register
whenever we try to use dwc3_gadget_wakeup() function.

Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 04048333ec1a3e971f86e0d964acf87e12070793..867c476853ecaa06360298fcb07aaaaf31bef1b2 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1307,6 +1307,7 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
        /* Recent versions do this automatically */
        if (dwc->revision < DWC3_REVISION_194A) {
                /* write zeroes to Link Change Request */
+               reg = dwc3_readl(dwc->regs, DWC3_DCTL);
                reg &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
                dwc3_writel(dwc->regs, DWC3_DCTL, reg);
        }