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usb: Add support for indicating whether a port is removable 

Userspace may want to make policy decisions based on whether or not a
given USB device is removable. Add a per-device member and support
for exposing it in sysfs. Information sources to populate it will be
added later.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Matthew Garrett 2012-02-03 17:11:54 -05:00 committed by Greg Kroah-Hartman
parent af74d2dae8
commit 0846e7e985
3 changed files with 42 additions and 0 deletions
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11
Documentation/ABI/testing/sysfs-bus-usb
View File

@ -182,3 +182,14 @@ Description:
USB2 hardware LPM is enabled for the device. Developer can
write y/Y/1 or n/N/0 to the file to enable/disable the
feature.
What: /sys/bus/usb/devices/.../removable
Date: February 2012
Contact: Matthew Garrett <mjg@redhat.com>
Description:
Some information about whether a given USB device is
physically fixed to the platform can be inferred from a
combination of hub decriptor bits and platform-specific data
such as ACPI. This file will read either "removable" or
"fixed" if the information is available, and "unknown"
otherwise.

23
drivers/usb/core/sysfs.c
View File

@ -230,6 +230,28 @@ show_urbnum(struct device *dev, struct device_attribute *attr, char *buf)
}
static DEVICE_ATTR(urbnum, S_IRUGO, show_urbnum, NULL);
static ssize_t
show_removable(struct device *dev, struct device_attribute *attr, char *buf)
{
struct usb_device *udev;
char *state;
udev = to_usb_device(dev);
switch (udev->removable) {
case USB_DEVICE_REMOVABLE:
state = "removable";
break;
case USB_DEVICE_FIXED:
state = "fixed";
break;
default:
state = "unknown";
}
return sprintf(buf, "%s\n", state);
}
static DEVICE_ATTR(removable, S_IRUGO, show_removable, NULL);
#ifdef CONFIG_PM
@ -626,6 +648,7 @@ static struct attribute *dev_attrs[] = {
&dev_attr_avoid_reset_quirk.attr,
&dev_attr_authorized.attr,
&dev_attr_remove.attr,
&dev_attr_removable.attr,
NULL,
};
static struct attribute_group dev_attr_grp = {

8
include/linux/usb.h
View File

@ -376,6 +376,12 @@ struct usb_bus {
struct usb_tt;
enum usb_device_removable {
USB_DEVICE_REMOVABLE_UNKNOWN = 0,
USB_DEVICE_REMOVABLE,
USB_DEVICE_FIXED,
};
/**
* struct usb_device - kernel's representation of a USB device
* @devnum: device number; address on a USB bus
@ -432,6 +438,7 @@ struct usb_tt;
* @wusb_dev: if this is a Wireless USB device, link to the WUSB
* specific data for the device.
* @slot_id: Slot ID assigned by xHCI
* @removable: Device can be physically removed from this port
*
* Notes:
* Usbcore drivers should not set usbdev->state directly. Instead use
@ -509,6 +516,7 @@ struct usb_device {
#endif
struct wusb_dev *wusb_dev;
int slot_id;
enum usb_device_removable removable;
};
#define to_usb_device(d) container_of(d, struct usb_device, dev)