USB: deprecate the power/level sysfs attribute

This patch (as1367) deprecates USB's power/level sysfs attribute in
favor of the power/control attribute provided by the runtime PM core.
The two attributes do the same thing.

It would be nice to replace power/level with a symlink to
power/control, but at the moment sysfs doesn't offer any way to do so.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index b65c1eaf3aba..06863befaf3a 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -383,12 +383,23 @@ static DEVICE_ATTR(autosuspend, S_IRUGO | S_IWUSR,
 static const char on_string[] = "on";
 static const char auto_string[] = "auto";
 
+static void warn_level(void) {
+        static int level_warned;
+
+        if (!level_warned) {
+                level_warned = 1;
+                printk(KERN_WARNING "WARNING! power/level is deprecated; "
+                                "use power/control instead\n");
+        }
+}
+
 static ssize_t
 show_level(struct device *dev, struct device_attribute *attr, char *buf)
 {
         struct usb_device *udev = to_usb_device(dev);
         const char *p = auto_string;
 
+        warn_level();
         if (udev->state != USB_STATE_SUSPENDED && !udev->dev.power.runtime_auto)
                 p = on_string;
         return sprintf(buf, "%s\n", p);
@@ -403,6 +414,7 @@ set_level(struct device *dev, struct device_attribute *attr,
         char *cp;
         int rc = count;
 
+        warn_level();
         cp = memchr(buf, '\n', count);
         if (cp)
                 len = cp - buf;