[v5,01/10] usb: dwc3: Add SoftReset PHY synchonization delay

[v5,01/10] usb: dwc3: Add SoftReset PHY synchonization delay

[Thinh Nguyen]

From DWC_usb31 programming guide section 1.3.2, once DWC3_DCTL_CSFTRST
bit is cleared, we must wait at least 50ms before accessing the PHY
domain (synchronization delay).

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
---
 drivers/usb/dwc3/core.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index e8890c0201a5..5491d9678d70 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -244,7 +244,7 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
 	do {
 		reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 		if (!(reg & DWC3_DCTL_CSFTRST))
-			return 0;
+			goto done;
 
 		udelay(1);
 	} while (--retries);
@@ -253,6 +253,17 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
 	phy_exit(dwc->usb2_generic_phy);
 
 	return -ETIMEDOUT;
+
+done:
+	/*
+	 * For DWC_usb31 controller, once DWC3_DCTL_CSFTRST bit is cleared,
+	 * we must wait at least 50ms before accessing the PHY domain
+	 * (synchronization delay). DWC_usb31 programming guide section 1.3.2.
+	 */
+	if (dwc3_is_usb31(dwc))
+		msleep(50);
+
+	return 0;
 }
 
 /*