usb: dwc2: drd: add role-switch-default-node support

When using usb-role-switch, while the usb role is not yet define
(USB_ROLE_NONE), the user may want to configure the default mode to host
or device.
Use role-switch-default-mode for that purpose.
Acked-by: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/1638806203-6624-3-git-send-email-fabrice.gasnier@foss.st.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc2/core.h

@@ -869,6 +869,8 @@ struct dwc2_hregs_backup {
  *                      - USB_DR_MODE_HOST
  *                      - USB_DR_MODE_OTG
  * @role_sw:		usb_role_switch handle
+ * @role_sw_default_mode: default operation mode of controller while usb role
+ *			is USB_ROLE_NONE
  * @hcd_enabled:	Host mode sub-driver initialization indicator.
  * @gadget_enabled:	Peripheral mode sub-driver initialization indicator.
  * @ll_hw_enabled:	Status of low-level hardware resources.
@@ -1065,6 +1067,7 @@ struct dwc2_hsotg {
 	enum usb_otg_state op_state;
 	enum usb_dr_mode dr_mode;
 	struct usb_role_switch *role_sw;
+	enum usb_dr_mode role_sw_default_mode;
 	unsigned int hcd_enabled:1;
 	unsigned int gadget_enabled:1;
 	unsigned int ll_hw_enabled:1;

drivers/usb/dwc2/drd.c

@@ -24,6 +24,10 @@ static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
 	gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN;
 	gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS;
 	gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
+	if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
+		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
+	else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
+		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
 	dwc2_writel(hsotg, gotgctl, GOTGCTL);
 
 	spin_unlock_irqrestore(&hsotg->lock, flags);
@@ -105,6 +109,14 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 
 	spin_lock_irqsave(&hsotg->lock, flags);
 
+	if (role == USB_ROLE_NONE) {
+		/* default operation mode when usb role is USB_ROLE_NONE */
+		if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
+			role = USB_ROLE_HOST;
+		else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
+			role = USB_ROLE_DEVICE;
+	}
+
 	if (role == USB_ROLE_HOST) {
 		already = dwc2_ovr_avalid(hsotg, true);
 	} else if (role == USB_ROLE_DEVICE) {
@@ -146,6 +158,7 @@ int dwc2_drd_init(struct dwc2_hsotg *hsotg)
 	if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
 		return 0;
 
+	hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(hsotg->dev);
 	role_sw_desc.driver_data = hsotg;
 	role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
 	role_sw_desc.set = dwc2_drd_role_sw_set;