[PATCH 2.6.20.1] fix ftdi_sio sysfs attributes (latency_timer, event_char)

Edwin Olson <[email protected]>
Newsgroups gmane.linux.usb.devel,gmane.spam.detected
Message-ID <[email protected]> 
Somewhere around 2.6.18, reading or writing the sysfs attributes for the 
ftdi_sio driver started causing seg faults; the wrong dev structure was 
being accessed.

This patch fixes the problem, and fixes a conceptual error in the 
original implementation which assumed that there was only one port (and 
one set of attributes) per usb device. However, multi-port devices each 
have their own set of registers (or at least the ftdi protocol permits 
this). This patch creates a set of attributes for each *port*, not 
merely each usb device, and the sysfs attributes will now appear one 
directory deeper in /sys, as attributes of the usb_serial_port, rather 
than the parent usb device. (In other words, the attributes will appear 
in the ttyUSBxx directory).

Tested on 2.6.20-1 and 2.6.19-1, this patch is against 2.6.20-1.

Signed-off-by: Edwin Olson <[email protected]>

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patch (text/plain, 4.9 KB) 
--- linux-2.6.20.1/drivers/usb/serial/ftdi_sio.c	2007-02-20 01:34:32.000000000 -0500
+++ linux-2.6.20.1-eolson/drivers/usb/serial/ftdi_sio.c	2007-03-01 19:55:46.000000000 -0500
@@ -520,9 +520,11 @@
 
 MODULE_DEVICE_TABLE (usb, id_table_combined);
 
+static int  ftdi_device_probe           (struct usb_interface *interface,  const struct usb_device_id *id);
+
 static struct usb_driver ftdi_driver = {
 	.name =		"ftdi_sio",
-	.probe =	usb_serial_probe,
+	.probe =	ftdi_device_probe,
 	.disconnect =	usb_serial_disconnect,
 	.id_table =	id_table_combined,
 	.no_dynamic_id =	1,
@@ -585,7 +587,7 @@
  ASYNC_SPD_CUST | ASYNC_SPD_SHI | ASYNC_SPD_WARP )
 
 /* function prototypes for a FTDI serial converter */
-static int  ftdi_sio_probe	(struct usb_serial *serial, const struct usb_device_id *id);
+static int  ftdi_sio_probe      	(struct usb_serial *serial, const struct usb_device_id *id);
 static int  ftdi_sio_attach		(struct usb_serial *serial);
 static void ftdi_shutdown		(struct usb_serial *serial);
 static int  ftdi_open			(struct usb_serial_port *port, struct file *filp);
@@ -1023,12 +1025,10 @@
 {
 	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct ftdi_private *priv = usb_get_serial_port_data(port);
-	struct usb_device *udev;
+	struct usb_device *udev = port->serial->dev;
 	unsigned short latency = 0;
 	int rv = 0;
 
-	udev = to_usb_device(dev);
-
 	dbg("%s",__FUNCTION__);
 
 	rv = usb_control_msg(udev,
@@ -1051,13 +1051,12 @@
 {
 	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct ftdi_private *priv = usb_get_serial_port_data(port);
-	struct usb_device *udev;
+	struct usb_device *udev = port->serial->dev;
+
 	char buf[1];
 	int v = simple_strtoul(valbuf, NULL, 10);
 	int rv = 0;
 
-	udev = to_usb_device(dev);
-
 	dbg("%s: setting latency timer = %i", __FUNCTION__, v);
 
 	rv = usb_control_msg(udev,
@@ -1082,13 +1081,12 @@
 {
 	struct usb_serial_port *port = to_usb_serial_port(dev);
 	struct ftdi_private *priv = usb_get_serial_port_data(port);
-	struct usb_device *udev;
+	struct usb_device *udev = port->serial->dev;
+
 	char buf[1];
 	int v = simple_strtoul(valbuf, NULL, 10);
 	int rv = 0;
 
-	udev = to_usb_device(dev);
-
 	dbg("%s: setting event char = %i", __FUNCTION__, v);
 
 	rv = usb_control_msg(udev,
@@ -1109,17 +1107,14 @@
 static DEVICE_ATTR(latency_timer, S_IWUSR | S_IRUGO, show_latency_timer, store_latency_timer);
 static DEVICE_ATTR(event_char, S_IWUSR, NULL, store_event_char);
 
-static int create_sysfs_attrs(struct usb_serial *serial)
+static int create_sysfs_attrs(struct usb_serial_port *port)
 {
-	struct ftdi_private *priv;
-	struct usb_device *udev;
+	struct ftdi_private *priv = usb_get_serial_port_data(port);
+	struct usb_device *udev = to_usb_device(&port->dev);
 	int retval = 0;
 
 	dbg("%s",__FUNCTION__);
 
-	priv = usb_get_serial_port_data(serial->port[0]);
-	udev = serial->dev;
-
 	/* XXX I've no idea if the original SIO supports the event_char
 	 * sysfs parameter, so I'm playing it safe.  */
 	if (priv->chip_type != SIO) {
@@ -1134,16 +1129,13 @@
 	return retval;
 }
 
-static void remove_sysfs_attrs(struct usb_serial *serial)
+static void remove_sysfs_attrs(struct usb_serial_port *port)
 {
-	struct ftdi_private *priv;
-	struct usb_device *udev;
+	struct ftdi_private *priv = usb_get_serial_port_data(port);
+	struct usb_device *udev = to_usb_device(&port->dev);
 
 	dbg("%s",__FUNCTION__);
 
-	priv = usb_get_serial_port_data(serial->port[0]);
-	udev = serial->dev;
-
 	/* XXX see create_sysfs_attrs */
 	if (priv->chip_type != SIO) {
 		device_remove_file(&udev->dev, &dev_attr_event_char);
@@ -1154,6 +1146,22 @@
 
 }
 
+static int ftdi_device_probe(struct usb_interface *interface,
+			     const struct usb_device_id *id)
+{
+	int rv = usb_serial_probe(interface, id);
+	struct usb_serial *serial = usb_get_intfdata(interface);
+	int i;
+
+	if (!rv) {
+		for (i = 0; i < serial->num_ports; i++) {
+			create_sysfs_attrs(serial->port[i]);
+		}
+	}
+
+	return rv;
+}
+
 /*
  * ***************************************************************************
  * FTDI driver specific functions
@@ -1174,7 +1182,6 @@
 	struct usb_serial_port *port = serial->port[0];
 	struct ftdi_private *priv;
 	struct ftdi_sio_quirk *quirk;
-	int retval;
 
 	dbg("%s",__FUNCTION__);
 
@@ -1217,10 +1224,6 @@
 	usb_set_serial_port_data(serial->port[0], priv);
 
 	ftdi_determine_type (serial->port[0]);
-	retval = create_sysfs_attrs(serial);
-	if (retval)
-		dev_err(&serial->dev->dev, "Error creating sysfs files, "
-			"continuing\n");
 
 	/* Check for device requiring special set up. */
 	quirk = (struct ftdi_sio_quirk *)usb_get_serial_data(serial);
@@ -1277,10 +1280,12 @@
 
 	struct usb_serial_port *port = serial->port[0];
 	struct ftdi_private *priv = usb_get_serial_port_data(port);
+	int i;
 
 	dbg("%s", __FUNCTION__);
 
-	remove_sysfs_attrs(serial);
+	for (i = 0; i < serial->num_ports; i++)
+		remove_sysfs_attrs(serial->port[i]);
 
 	/* all open ports are closed at this point
          *    (by usbserial.c:__serial_close, which calls ftdi_close)
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