[PATCH] USB: Export IEEE-1284 device id in sysfs for usblp devices

I looked at the userspace code which uses the LPIOC_GET_DEVICE_ID ioctl
and I almost went blind. Let's export it in sysfs instead, and just as a
string instead of with a big-endian length at the beginning of it.

This also prints the message about finding the printer _after_ we know
the minor device number it's going to have, rather than reporting all
printers as 'usblp0'.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 26 insertions, 9 deletions

diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index 708a292e5a0d..27e9404547f3 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -850,6 +850,20 @@ static struct usb_class_driver usblp_class = {
         .minor_base =   USBLP_MINOR_BASE,
 };
 
+static ssize_t usblp_show_ieee1284_id(struct device *dev, struct device_attribute *attr, char *buf)
+{
+        struct usb_interface *intf = to_usb_interface(dev);
+        struct usblp *usblp = usb_get_intfdata (intf);
+
+        if (usblp->device_id_string[0] == 0 &&
+            usblp->device_id_string[1] == 0)
+                return 0;
+
+        return sprintf(buf, "%s", usblp->device_id_string+2);
+}
+
+static DEVICE_ATTR(ieee1284_id, S_IRUGO, usblp_show_ieee1284_id, NULL);
+
 static int usblp_probe(struct usb_interface *intf,
                        const struct usb_device_id *id)
 {
@@ -934,20 +948,12 @@ static int usblp_probe(struct usb_interface *intf,
 
         /* Retrieve and store the device ID string. */
         usblp_cache_device_id_string(usblp);
+        device_create_file(&intf->dev, &dev_attr_ieee1284_id);
 
 #ifdef DEBUG
         usblp_check_status(usblp, 0);
 #endif
 
-        info("usblp%d: USB %sdirectional printer dev %d "
-                "if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X",
-                usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
-                usblp->ifnum,
-                usblp->protocol[usblp->current_protocol].alt_setting,
-                usblp->current_protocol,
-                le16_to_cpu(usblp->dev->descriptor.idVendor),
-                le16_to_cpu(usblp->dev->descriptor.idProduct));
-
         usb_set_intfdata (intf, usblp);
 
         usblp->present = 1;
@@ -958,11 +964,20 @@ static int usblp_probe(struct usb_interface *intf,
                 goto abort_intfdata;
         }
         usblp->minor = intf->minor;
+        info("usblp%d: USB %sdirectional printer dev %d "
+                "if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X",
+                usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
+                usblp->ifnum,
+                usblp->protocol[usblp->current_protocol].alt_setting,
+                usblp->current_protocol,
+                le16_to_cpu(usblp->dev->descriptor.idVendor),
+                le16_to_cpu(usblp->dev->descriptor.idProduct));
 
         return 0;
 
 abort_intfdata:
         usb_set_intfdata (intf, NULL);
+        device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
 abort:
         if (usblp) {
                 if (usblp->writebuf)
@@ -1157,6 +1172,8 @@ static void usblp_disconnect(struct usb_interface *intf)
                 BUG ();
         }
 
+        device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
+
         down (&usblp_sem);
         down (&usblp->sem);
         usblp->present = 0;