usb: dwc2: gadget: implement udc_set_speed()

Implemented udc_set_speed() gadget ops to allow the udc to select
the gadget speed on initialization.
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Signed-off-by: Argishti Aleksanyan <aleksan@synopsys.com>
Link: https://lore.kernel.org/r/c453469d618100321c876a8c2b0ebee15a456eac.1628583235.git.aleksan@synopsys.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc2/gadget.c

@@ -4709,12 +4709,35 @@ static int dwc2_hsotg_vbus_draw(struct usb_gadget *gadget, unsigned int mA)
 	return usb_phy_set_power(hsotg->uphy, mA);
 }
 
+static void dwc2_gadget_set_speed(struct usb_gadget *g, enum usb_device_speed speed)
+{
+	struct dwc2_hsotg *hsotg = to_hsotg(g);
+	unsigned long		flags;
+
+	spin_lock_irqsave(&hsotg->lock, flags);
+	switch (speed) {
+	case USB_SPEED_HIGH:
+		hsotg->params.speed = DWC2_SPEED_PARAM_HIGH;
+		break;
+	case USB_SPEED_FULL:
+		hsotg->params.speed = DWC2_SPEED_PARAM_FULL;
+		break;
+	case USB_SPEED_LOW:
+		hsotg->params.speed = DWC2_SPEED_PARAM_LOW;
+		break;
+	default:
+		dev_err(hsotg->dev, "invalid speed (%d)\n", speed);
+	}
+	spin_unlock_irqrestore(&hsotg->lock, flags);
+}
+
 static const struct usb_gadget_ops dwc2_hsotg_gadget_ops = {
 	.get_frame	= dwc2_hsotg_gadget_getframe,
 	.set_selfpowered	= dwc2_hsotg_set_selfpowered,
 	.udc_start		= dwc2_hsotg_udc_start,
 	.udc_stop		= dwc2_hsotg_udc_stop,
 	.pullup                 = dwc2_hsotg_pullup,
+	.udc_set_speed		= dwc2_gadget_set_speed,
 	.vbus_session		= dwc2_hsotg_vbus_session,
 	.vbus_draw		= dwc2_hsotg_vbus_draw,
 };