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List:       linux-usb
Subject:    [RFC] add devpath sysfs attribute
From:       Greg KH <greg () kroah ! com>
Date:       2009-11-30 19:18:16
Message-ID: 20091130191816.GA9305 () kroah ! com
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For some reason, I know this has come up in the past, but I can't
remember why we don't export the devpath usb field to userspace through
sysfs.

I'm looking at rewriting 'lsusb' to use sysfs instead of libusb, and
find it handy to have the devpath as an easy-to-read field to help
determine how to find the interface devices attached to this device.

Any objections to this patch being added?

thanks,

greg k-h

-------------
Date: Mon, 30 Nov 2009 11:15:02 -0800
From: Greg Kroah-Hartman <gregkh@suse.de>
Subject: USB: add devpath sysfs attribute

This is not exported from the usb core, yet we rely on it to create
paths to interfaces for this device in sysfs.  Export it to make
userspace tools have an easier time to figure things out.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/usb/core/sysfs.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -139,6 +139,16 @@ show_devnum(struct device *dev, struct d
 static DEVICE_ATTR(devnum, S_IRUGO, show_devnum, NULL);
 
 static ssize_t
+show_devpath(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct usb_device *udev;
+
+	udev = to_usb_device(dev);
+	return sprintf(buf, "%s\n", udev->devpath);
+}
+static DEVICE_ATTR(devpath, S_IRUGO, show_devpath, NULL);
+
+static ssize_t
 show_version(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	struct usb_device *udev;
@@ -538,8 +548,8 @@ static struct attribute *dev_attrs[] = {
 	&dev_attr_bConfigurationValue.attr,
 	&dev_attr_bmAttributes.attr,
 	&dev_attr_bMaxPower.attr,
-	&dev_attr_urbnum.attr,
 	/* device attributes */
+	&dev_attr_urbnum.attr,
 	&dev_attr_idVendor.attr,
 	&dev_attr_idProduct.attr,
 	&dev_attr_bcdDevice.attr,
@@ -551,6 +561,7 @@ static struct attribute *dev_attrs[] = {
 	&dev_attr_speed.attr,
 	&dev_attr_busnum.attr,
 	&dev_attr_devnum.attr,
+	&dev_attr_devpath.attr,
 	&dev_attr_version.attr,
 	&dev_attr_maxchild.attr,
 	&dev_attr_quirks.attr,
--
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