sandbox: usb: Allow finding a USB emulator for a device

Each USB device has an emulator. Currently this can only be found by
supplying the 'pipe' value, which contains the device number. Add a way
to find it directly from the emulated device.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/usb/emul/usb-emul-uclass.c

@@ -108,9 +108,8 @@ static int usb_emul_get_descriptor(struct usb_dev_platdata *plat, int value,
 	return upto ? upto : length ? -EIO : 0;
 }
 
-int usb_emul_find(struct udevice *bus, ulong pipe, struct udevice **emulp)
+static int usb_emul_find_devnum(int devnum, struct udevice **emulp)
 {
-	int devnum = usb_pipedevice(pipe);
 	struct udevice *dev;
 	struct uclass *uc;
 	int ret;
@@ -134,6 +133,20 @@ int usb_emul_find(struct udevice *bus, ulong pipe, struct udevice **emulp)
 	return -ENOENT;
 }
 
+int usb_emul_find(struct udevice *bus, ulong pipe, struct udevice **emulp)
+{
+	int devnum = usb_pipedevice(pipe);
+
+	return usb_emul_find_devnum(devnum, emulp);
+}
+
+int usb_emul_find_for_dev(struct udevice *dev, struct udevice **emulp)
+{
+	struct usb_dev_platdata *udev = dev_get_parent_platdata(dev);
+
+	return usb_emul_find_devnum(udev->devnum, emulp);
+}
+
 int usb_emul_control(struct udevice *emul, struct usb_device *udev,
 		     unsigned long pipe, void *buffer, int length,
 		     struct devrequest *setup)

include/usb.h

@@ -950,6 +950,16 @@ int usb_emul_bulk(struct udevice *emul, struct usb_device *udev,
 int usb_emul_find(struct udevice *bus, ulong pipe, struct udevice **emulp);
 
 /**
+ * usb_emul_find_for_dev() - Find an emulator for a particular device
+ *
+ * @bus:	USB bus (controller)
+ * @dev:	USB device to check
+ * @emulp:	Returns pointer to emulator, or NULL if not found
+ * @return 0 if found, -ve on error
+ */
+int usb_emul_find_for_dev(struct udevice *dev, struct udevice **emulp);
+
+/**
  * usb_emul_reset() - Reset all emulators ready for use
  *
  * Clear out any address information in the emulators and make then ready for