4 files changed, 34 insertions, 6 deletions

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index d83be5651f87..a666e0758a99 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -985,6 +985,7 @@ struct dwc2_hsotg {
 
 	/* DWC OTG HW Release versions */
 #define DWC2_CORE_REV_2_71a	0x4f54271a
+#define DWC2_CORE_REV_2_72a     0x4f54272a
 #define DWC2_CORE_REV_2_80a	0x4f54280a
 #define DWC2_CORE_REV_2_90a	0x4f54290a
 #define DWC2_CORE_REV_2_91a	0x4f54291a
@@ -992,6 +993,7 @@ struct dwc2_hsotg {
 #define DWC2_CORE_REV_2_94a	0x4f54294a
 #define DWC2_CORE_REV_3_00a	0x4f54300a
 #define DWC2_CORE_REV_3_10a	0x4f54310a
+#define DWC2_CORE_REV_4_00a	0x4f54400a
 #define DWC2_FS_IOT_REV_1_00a	0x5531100a
 #define DWC2_HS_IOT_REV_1_00a	0x5532100a
 
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 6c32bf26e48e..83cb5577a52f 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3928,6 +3928,27 @@ static int dwc2_hsotg_ep_enable(struct usb_ep *ep,
 	if (index && !hs_ep->isochronous)
 		epctrl |= DXEPCTL_SETD0PID;
 
+	/* WA for Full speed ISOC IN in DDMA mode.
+	 * By Clear NAK status of EP, core will send ZLP
+	 * to IN token and assert NAK interrupt relying
+	 * on TxFIFO status only
+	 */
+
+	if (hsotg->gadget.speed == USB_SPEED_FULL &&
+	    hs_ep->isochronous && dir_in) {
+		/* The WA applies only to core versions from 2.72a
+		 * to 4.00a (including both). Also for FS_IOT_1.00a
+		 * and HS_IOT_1.00a.
+		 */
+		u32 gsnpsid = dwc2_readl(hsotg->regs + GSNPSID);
+
+		if ((gsnpsid >= DWC2_CORE_REV_2_72a &&
+		     gsnpsid <= DWC2_CORE_REV_4_00a) ||
+		     gsnpsid == DWC2_FS_IOT_REV_1_00a ||
+		     gsnpsid == DWC2_HS_IOT_REV_1_00a)
+			epctrl |= DXEPCTL_CNAK;
+	}
+
 	dev_dbg(hsotg->dev, "%s: write DxEPCTL=0x%08x\n",
 		__func__, epctrl);
 
diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 190f95964000..c51b73b3e048 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -358,9 +358,14 @@ static void dwc2_gusbcfg_init(struct dwc2_hsotg *hsotg)
 
 static int dwc2_vbus_supply_init(struct dwc2_hsotg *hsotg)
 {
+	int ret;
+
 	hsotg->vbus_supply = devm_regulator_get_optional(hsotg->dev, "vbus");
-	if (IS_ERR(hsotg->vbus_supply))
-		return 0;
+	if (IS_ERR(hsotg->vbus_supply)) {
+		ret = PTR_ERR(hsotg->vbus_supply);
+		hsotg->vbus_supply = NULL;
+		return ret == -ENODEV ? 0 : ret;
+	}
 
 	return regulator_enable(hsotg->vbus_supply);
 }
@@ -4342,9 +4347,7 @@ static int _dwc2_hcd_start(struct usb_hcd *hcd)
 
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 
-	dwc2_vbus_supply_init(hsotg);
-
-	return 0;
+	return dwc2_vbus_supply_init(hsotg);
 }
 
 /*
diff --git a/drivers/usb/dwc2/pci.c b/drivers/usb/dwc2/pci.c
index 7f21747007f1..bea2e8ec0369 100644
--- a/drivers/usb/dwc2/pci.c
+++ b/drivers/usb/dwc2/pci.c
@@ -141,8 +141,10 @@ static int dwc2_pci_probe(struct pci_dev *pci,
 		goto err;
 
 	glue = devm_kzalloc(dev, sizeof(*glue), GFP_KERNEL);
-	if (!glue)
+	if (!glue) {
+		ret = -ENOMEM;
 		goto err;
+	}
 
 	ret = platform_device_add(dwc2);
 	if (ret) {