media: em28xx-core: Fix i2c error debug

Read errors are currently reported as write errors.

An incorrectly received read operation is never reported at all.
Add a debug statement indicating the request mismatch.
Signed-off-by: Brad Love <brad@nextdimension.cc>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/usb/em28xx/em28xx-i2c.c

@@ -294,6 +294,10 @@ static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len)
 			 "reading from i2c device at 0x%x failed (error=%i)\n",
 			 addr, ret);
 		return ret;
+	} else if (ret != len) {
+		dev_dbg(&dev->intf->dev,
+			"%i bytes read from i2c device at 0x%x requested, but %i bytes written\n",
+				ret, addr, len);
 	}
 	/*
 	 * NOTE: some devices with two i2c buses have the bad habit to return 0
@@ -329,7 +333,7 @@ static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len)
 	}
 
 	dev_warn(&dev->intf->dev,
-		 "write to i2c device at 0x%x failed with unknown error (status=%i)\n",
+		 "read from i2c device at 0x%x failed with unknown error (status=%i)\n",
 		 addr, ret);
 	return -EIO;
 }