usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host

Take into account gadget driver's speed limit when programming
controller speed.

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Roger Quadros <rogerq@ti.com>
Acked-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20191030121607.21739-1-rogerq@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 26 insertions, 5 deletions

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 8421fc028c40..4c1e75509303 100644
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -2343,9 +2343,35 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
 {
         struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
         unsigned long flags;
+        enum usb_device_speed max_speed = driver->max_speed;
 
         spin_lock_irqsave(&priv_dev->lock, flags);
         priv_dev->gadget_driver = driver;
+
+        /* limit speed if necessary */
+        max_speed = min(driver->max_speed, gadget->max_speed);
+
+        switch (max_speed) {
+        case USB_SPEED_FULL:
+                writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
+                writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
+                break;
+        case USB_SPEED_HIGH:
+                writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
+                break;
+        case USB_SPEED_SUPER:
+                break;
+        default:
+                dev_err(priv_dev->dev,
+                        "invalid maximum_speed parameter %d\n",
+                        max_speed);
+                /* fall through */
+        case USB_SPEED_UNKNOWN:
+                /* default to superspeed */
+                max_speed = USB_SPEED_SUPER;
+                break;
+        }
+
         cdns3_gadget_config(priv_dev);
         spin_unlock_irqrestore(&priv_dev->lock, flags);
         return 0;
@@ -2575,12 +2601,7 @@ static int cdns3_gadget_start(struct cdns3 *cdns)
         /* Check the maximum_speed parameter */
         switch (max_speed) {
         case USB_SPEED_FULL:
-                writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
-                writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
-                break;
         case USB_SPEED_HIGH:
-                writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
-                break;
         case USB_SPEED_SUPER:
                 break;
         default: