Patch "USB: serial: cp210x: fix partnum regression" has been added to the 4.13-stable tree

This is a note to let you know that I've just added the patch titled

    USB: serial: cp210x: fix partnum regression

to the 4.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     usb-serial-cp210x-fix-partnum-regression.patch

and it can be found in the queue-4.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sebastian Frei <[email protected]>
Date: Tue, 12 Sep 2017 09:50:59 +0200
Subject: USB: serial: cp210x: fix partnum regression

From: Sebastian Frei <[email protected]>

commit 7eac35ea29dc54cbc8399de84c9bf16553575b89 upstream.

When adding GPIO support for the cp2105, the mentioned commit by Martyn Welch introduced a query for the part number of the chip. Unfortunately the driver aborts probing when this query fails, so currently the driver can not be used with chips not supporting this query.
I have a data cable for Siemens mobile phones (ID 10ab:10c5) where this is the case.
With this patch the driver can be bound even if the part number can not be queried.

[ johan: amend commit message; shorten error message and demote to
warning; drop unnecessary move of usb_set_serial_data() ]

---
 drivers/usb/serial/cp210x.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

@@ -352,6 +352,7 @@ static struct usb_serial_driver * const
 #define CP210X_PARTNUM_CP2104	0x04
 #define CP210X_PARTNUM_CP2105	0x05
 #define CP210X_PARTNUM_CP2108	0x08
+#define CP210X_PARTNUM_UNKNOWN	0xFF
 
 /* CP210X_GET_COMM_STATUS returns these 0x13 bytes */
 struct cp210x_comm_status {

@@ -1491,8 +1492,11 @@ static int cp210x_attach(struct usb_seri
 	result = cp210x_read_vendor_block(serial, REQTYPE_DEVICE_TO_HOST,
 					  CP210X_GET_PARTNUM, &priv->partnum,
 					  sizeof(priv->partnum));
-	if (result < 0)
-		goto err_free_priv;
+	if (result < 0) {
+		dev_warn(&serial->interface->dev,
+			 "querying part number failed\n");
+		priv->partnum = CP210X_PARTNUM_UNKNOWN;
+	}
 
 	usb_set_serial_data(serial, priv);
 

@@ -1505,10 +1509,6 @@ static int cp210x_attach(struct usb_seri
 	}
 
 	return 0;
-err_free_priv:
-	kfree(priv);
-
-	return result;
 }
 
 static void cp210x_disconnect(struct usb_serial *serial)

Patches currently in stable-queue which might be from [email protected] are

queue-4.13/usb-serial-cp210x-fix-partnum-regression.patch