af9015 usb bus repeater.

index 9077ac4..ac134b6 100644
@@ -68,7 +68,7 @@ static struct af9013_config af9015_af9013_config[] = {
 	}
 };
 
-static int af9015_rw_udev(struct usb_device *udev, struct req_t *req)
+static int af9015_io_udev(struct usb_device *udev, struct req_t *req)
 {
 #define BUF_LEN 63
 #define REQ_HDR_LEN 8 /* send header size */

@@ -79,9 +79,6 @@ static int af9015_rw_udev(struct usb_device *udev, struct req_t *req)
 	u8 msg_len = REQ_HDR_LEN;
 	static u8 seq; /* packet sequence number */
 
-	if (mutex_lock_interruptible(&af9015_usb_mutex) < 0)
-		return -EAGAIN;
-
 	buf[0] = req->cmd;
 	buf[1] = seq++;
 	buf[2] = req->i2c_addr;

@@ -114,16 +111,14 @@ static int af9015_rw_udev(struct usb_device *udev, struct req_t *req)
 		break;
 	default:
 		err("unknown command:%d", req->cmd);
-		ret = -1;
-		goto error_unlock;
+		return -EINVAL;
 	}
 
 	/* buffer overflow check */
 	if ((write && (req->data_len > BUF_LEN - REQ_HDR_LEN)) ||
 		(!write && (req->data_len > BUF_LEN - ACK_HDR_LEN))) {
 		err("too much data; cmd:%d len:%d", req->cmd, req->data_len);
-		ret = -EINVAL;
-		goto error_unlock;
+		return -EINVAL;
 	}
 
 	/* write requested */

@@ -142,13 +137,13 @@ static int af9015_rw_udev(struct usb_device *udev, struct req_t *req)
 		err("bulk message failed:%d (%d/%d)", ret, msg_len, act_len);
 	else
 		if (act_len != msg_len)
-			ret = -1; /* all data is not send */
+			return -EAGAIN; /* all data is not send */
 	if (ret)
-		goto error_unlock;
+		goto error;
 
 	/* no ack for those packets */
 	if (req->cmd == DOWNLOAD_FIRMWARE || req->cmd == RECONNECT_USB)
-		goto exit_unlock;
+		return 0;
 
 	/* write receives seq + status = 2 bytes
 	   read receives seq + status + data = 2 + N bytes */

@@ -158,30 +153,48 @@ static int af9015_rw_udev(struct usb_device *udev, struct req_t *req)
 
 	ret = usb_bulk_msg(udev, usb_rcvbulkpipe(udev, 0x81), buf, msg_len,
 		&act_len, AF9015_USB_TIMEOUT);
-	if (ret) {
-		err("recv bulk message failed:%d", ret);
-		ret = -1;
-		goto error_unlock;
-	}
+	if (ret)
+		goto error;
 
 	deb_xfer("<<< ");
 	debug_dump(buf, act_len, deb_xfer);
 
 	/* check status */
-	if (buf[1]) {
-		err("command failed:%d", buf[1]);
-		ret = -1;
-		goto error_unlock;
-	}
+	if (buf[1])
+		return -EAGAIN;
 
 	/* read request, copy returned data to return buf */
 	if (!write)
 		memcpy(req->data, &buf[ACK_HDR_LEN], req->data_len);
 
-error_unlock:
-exit_unlock:
-	mutex_unlock(&af9015_usb_mutex);
+error:
+	if (ret == -ETIMEDOUT || ret == -EBUSY)
+		return -EAGAIN;
+
+	return ret;
+}
+
+#define AF9015_RETRY 5
+static int af9015_rw_udev(struct usb_device *udev, struct req_t *req)
+{
+	int ret = 0, i;
+
+	if (mutex_lock_interruptible(&af9015_usb_mutex) < 0)
+		return -EAGAIN;
+
+	for (i = 0; i < AF9015_RETRY; i++) {
+		if (req == NULL)
+			break;
+		ret = af9015_io_udev(udev, req);
+		if (ret != -EAGAIN)
+			break;
+		udelay(250);
+	}
+	if (ret && req)
+		err("Command failed:%x i2c addr:%x error:%d",
+			req->cmd, req->i2c_addr, ret);
 
+	mutex_unlock(&af9015_usb_mutex);
 	return ret;
 }