usb: typec: fusb302: Use usb_debug_root as root for our debugfs entry

Use usb_debug_root as root for our debugfs entry instead of creating our
own subdirectory under the debugfs root.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20190817184340.64086-2-hdegoede@redhat.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/tcpm/fusb302.c

@@ -26,6 +26,7 @@
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/types.h>
+#include <linux/usb.h>
 #include <linux/usb/typec.h>
 #include <linux/usb/tcpm.h>
 #include <linux/usb/pd.h>
@@ -206,23 +207,19 @@ static int fusb302_debug_show(struct seq_file *s, void *v)
 }
 DEFINE_SHOW_ATTRIBUTE(fusb302_debug);
 
-static struct dentry *rootdir;
-
 static void fusb302_debugfs_init(struct fusb302_chip *chip)
 {
-	mutex_init(&chip->logbuffer_lock);
-	if (!rootdir)
-		rootdir = debugfs_create_dir("fusb302", NULL);
+	char name[NAME_MAX];
 
-	chip->dentry = debugfs_create_file(dev_name(chip->dev),
-					   S_IFREG | 0444, rootdir,
+	mutex_init(&chip->logbuffer_lock);
+	snprintf(name, NAME_MAX, "fusb302-%s", dev_name(chip->dev));
+	chip->dentry = debugfs_create_file(name, S_IFREG | 0444, usb_debug_root,
 					   chip, &fusb302_debug_fops);
 }
 
 static void fusb302_debugfs_exit(struct fusb302_chip *chip)
 {
 	debugfs_remove(chip->dentry);
-	debugfs_remove(rootdir);
 }
 
 #else