usb: udc: implement DM versions of usb_gadget_initialize()/_release()/_handle_interrupt()

When DM_USB_GADGET the platform code for the USB device must be replaced by
calls to a USB device driver.

usb_gadget_initialize() probes the USB device driver.
usb_gadget_release() removes the USB device driver.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
diff --git a/drivers/usb/dwc3/dwc3-generic.c b/drivers/usb/dwc3/dwc3-generic.c
index ad3a116..47cc140 100644
--- a/drivers/usb/dwc3/dwc3-generic.c
+++ b/drivers/usb/dwc3/dwc3-generic.c
@@ -22,19 +22,9 @@
 #include "linux-compat.h"
 
 #if CONFIG_IS_ENABLED(DM_USB_GADGET)
-int usb_gadget_handle_interrupts(int index)
+int dm_usb_gadget_handle_interrupts(struct udevice *dev)
 {
-	struct dwc3 *priv;
-	struct udevice *dev;
-	int ret;
-
-	ret = uclass_first_device(UCLASS_USB_DEV_GENERIC, &dev);
-	if (!dev || ret) {
-		pr_err("No USB device found\n");
-		return -ENODEV;
-	}
-
-	priv = dev_get_priv(dev);
+	struct dwc3 *priv = dev_get_priv(dev);
 
 	dwc3_gadget_uboot_handle_interrupt(priv);
 
diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
index f5c30dd..34bea27 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -18,7 +18,8 @@
 #include <asm/cache.h>
 #include <asm/dma-mapping.h>
 #include <common.h>
-
+#include <dm.h>
+#include <dm/device-internal.h>
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 
@@ -351,3 +352,44 @@
 MODULE_DESCRIPTION("UDC Framework");
 MODULE_AUTHOR("Felipe Balbi <balbi@ti.com>");
 MODULE_LICENSE("GPL v2");
+
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
+#define MAX_UDC_DEVICES 4
+static struct udevice *dev_array[MAX_UDC_DEVICES];
+int usb_gadget_initialize(int index)
+{
+	int ret;
+	struct udevice *dev = NULL;
+
+	if (index < 0 || index >= ARRAY_SIZE(dev_array))
+		return -EINVAL;
+	if (dev_array[index])
+		return 0;
+	ret = uclass_get_device(UCLASS_USB_DEV_GENERIC, index, &dev);
+	if (!dev || ret) {
+		pr_err("No USB device found\n");
+		return -ENODEV;
+	}
+	dev_array[index] = dev;
+	return 0;
+}
+
+int usb_gadget_release(int index)
+{
+	int ret;
+
+	if (index < 0 || index >= ARRAY_SIZE(dev_array))
+		return -EINVAL;
+	ret = device_remove(dev_array[index], DM_REMOVE_NORMAL);
+	if (!ret)
+		dev_array[index] = NULL;
+	return ret;
+}
+
+int usb_gadget_handle_interrupts(int index)
+{
+	if (index < 0 || index >= ARRAY_SIZE(dev_array))
+		return -EINVAL;
+	return dm_usb_gadget_handle_interrupts(dev_array[index]);
+}
+#endif
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 40ca2d3..497798a 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -927,6 +927,12 @@
 
 extern int usb_gadget_handle_interrupts(int index);
 
+#if CONFIG_IS_ENABLED(DM_USB_GADGET)
+int usb_gadget_initialize(int index);
+int usb_gadget_release(int index);
+int dm_usb_gadget_handle_interrupts(struct udevice *dev);
+#else
+#include <usb.h>
 static inline int usb_gadget_initialize(int index)
 {
 	return board_usb_init(index, USB_INIT_DEVICE);
@@ -936,4 +942,6 @@
 {
 	return board_usb_cleanup(index, USB_INIT_DEVICE);
 }
+#endif
+
 #endif	/* __LINUX_USB_GADGET_H */