+/**
+ * sysfs_get_device_parent: opens up given device's parent and returns a
+ * reference to its sysfs_device
+ * @dev: sysfs_device whose parent is requested
+ * Returns sysfs_device of the parent on success and NULL on failure
+ */
+struct sysfs_device *sysfs_get_device_parent(struct sysfs_device *dev)
+{
+ unsigned char ppath[SYSFS_PATH_MAX], *tmp = NULL;
+
+ if (dev == NULL) {
+ errno = EINVAL;
+ return NULL;
+ }
+
+ if (dev->parent != NULL)
+ return (dev->parent);
+
+ memset(ppath, 0, SYSFS_PATH_MAX);
+ strcpy(ppath, dev->path);
+ tmp = strrchr(ppath, '/');
+ if (tmp == NULL) {
+ dprintf("Invalid path to device %s\n", ppath);
+ return NULL;
+ }
+ if (*(tmp +1) == '\0') {
+ *tmp = '\0';
+ tmp = strrchr(tmp, '/');
+ if (tmp == NULL) {
+ dprintf("Invalid path to device %s\n", ppath);
+ return NULL;
+ }
+ }
+ *tmp = '\0';
+
+ /*
+ * All "devices" have the "detach_state" attribute - validate here
+ */
+ strcat(ppath, "/detach_state");
+ if ((sysfs_path_is_file(ppath)) != 0) {
+ dprintf("Device at %s does not have a parent\n", dev->path);
+ return NULL;
+ }
+ tmp = strrchr(ppath, '/');
+ *tmp = '\0';
+ dev->parent = sysfs_open_device_path(ppath);
+ if (dev->parent == NULL) {
+ dprintf("Error opening device %s's parent at %s\n",
+ dev->bus_id, ppath);
+ return NULL;
+ }
+ return (dev->parent);
+}
+