-----Original Message-----
From: Greg KH [mailto:greg at kroah.com]
Sent: Friday, September 25, 2015 1:19 PM
To: Rob Groner <redacted>
Cc: kernelnewbies at kernelnewbies.org
Subject: Re: [PATCH] 8250_pci: Prevent Exar/RTD Boards from binding.

On Fri, Sep 25, 2015 at 11:46:29AM -0400, Rob Groner wrote:

quoted

Serial boards made by RTD using the Exar XR17V358 chip rely on the
extra capabilities of the Exar-provided driver to allow configuration
of the board.  When support for the Exar chip was added to the kernel
8250_pci driver, this then prevented easy use of the board by
customers for anything other than standard serial usage in RS232 mode.

This patch prevents RTD sub-vendor boards from being bound by the
8250_pci driver, if it uses the XR17V358 chip.  Other RTD boards using
Exar chips are not affected.

Signed-off-by Rob Groner [off-list ref]
---
 drivers/tty/serial/8250/8250_pci.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_pci.c

b/drivers/tty/serial/8250/8250_pci.c
index 68042dd..89baf7f 100644

--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c

@@ -359,6 +359,16 @@ static void pci_ni8430_exit(struct pci_dev *dev)
 	iounmap(p);
 }

+/*
+ * RTD Embedded Technologies, Inc. boards
+ * Prevent from being bound to 8250 driver  */ static int
+pci_xr17v35x_rtd_probe(struct pci_dev *dev) {
+	return -ENODEV;
+}
+
 /* SBS Technologies Inc. PMC-OCTPRO and P-OCTAL cards */  static int

sbs_setup(struct serial_private *priv, const struct pciserial_board
*board, @@ -2105,6 +2115,8 @@ pci_wch_ch38x_setup(struct

serial_private *priv,

quoted

 #define PCI_DEVICE_ID_PERICOM_PI7C9X7954	0x7954
 #define PCI_DEVICE_ID_PERICOM_PI7C9X7958	0x7958

+#define PCI_SUBVENDOR_ID_RTD		0x1435
+
 /* Unknown vendors/cards - this should not be in linux/pci_ids.h */
 #define PCI_SUBDEVICE_ID_UNKNOWN_0x1584	0x1584
 #define PCI_SUBDEVICE_ID_UNKNOWN_0x1588	0x1588

@@ -2608,6 +2620,14 @@ static struct pci_serial_quirk pci_serial_quirks[]

__refdata = {

quoted

 	{
 		.vendor = PCI_VENDOR_ID_EXAR,
 		.device = PCI_DEVICE_ID_EXAR_XR17V358,
+		.subvendor = PCI_SUBVENDOR_ID_RTD,
+		.subdevice	= PCI_ANY_ID,
+		.probe		= pci_xr17v35x_rtd_probe,
+		.setup		= pci_xr17v35x_setup,

Why do you need the .setup callback if you are just not wanting to bind to
this driver?

You're right, that doesn't need to be set.

Rob Groner