usb: introduce a separate config option for DM USB device

Using CONFIG_DM_USB for this purpose prevents using DM_USB for host and not
for device.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index d456beb..98f8343 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -52,6 +52,20 @@
 	depends on DM_USB
 	default y
 
+config DM_USB_GADGET
+	bool "Enable driver model for USB Gadget"
+	depends on DM_USB
+	help
+	  Enable driver model for USB Gadget (Peripheral
+	  mode)
+
+config SPL_DM_USB_GADGET
+	bool "Enable driver model for USB Gadget in sPL"
+	depends on SPL_DM_USB
+	help
+	  Enable driver model for USB Gadget in SPL
+	  (Peripheral mode)
+
 source "drivers/usb/host/Kconfig"
 
 source "drivers/usb/dwc3/Kconfig"
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index f1ca619..f9d8465 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -789,8 +789,7 @@
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("DesignWare USB3 DRD Controller Driver");
 
-#if CONFIG_IS_ENABLED(DM_USB)
-
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
 int dwc3_init(struct dwc3 *dwc)
 {
 	int ret;
diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
index 56c9fd6..ad3a116 100644
--- a/drivers/usb/dwc3/dwc3-generic.c
+++ b/drivers/usb/dwc3/dwc3-generic.c
@@ -21,8 +21,7 @@
 #include "gadget.h"
 #include "linux-compat.h"
 
-DECLARE_GLOBAL_DATA_PTR;
-
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
 int usb_gadget_handle_interrupts(int index)
 {
 	struct dwc3 *priv;
@@ -97,6 +96,7 @@
 	.priv_auto_alloc_size = sizeof(struct dwc3),
 	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
 };
+#endif
 
 static int dwc3_generic_bind(struct udevice *parent)
 {