drivers/usb/core/of.c

   1 /*
   2  * of.c         The helpers for hcd device tree support
   3  *
   4  * Copyright (C) 2016 Freescale Semiconductor, Inc.
   5  * Author: Peter Chen <peter.chen@freescale.com>
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2  of
   9  * the License as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/of.h>
  21 #include <linux/usb/of.h>
  22
  23 /**
  24  * usb_of_get_child_node - Find the device node match port number
  25  * @parent: the parent device node
  26  * @portnum: the port number which device is connecting
  27  *
  28  * Find the node from device tree according to its port number.
  29  *
  30  * Return: On success, a pointer to the device node, %NULL on failure.
  31  */
  32 struct device_node *usb_of_get_child_node(struct device_node *parent,
  33                                         int portnum)
  34 {
  35         struct device_node *node;
  36         u32 port;
  37
  38         for_each_child_of_node(parent, node) {
  39                 if (!of_property_read_u32(node, "reg", &port)) {
  40                         if (port == portnum)
  41                                 return node;
  42                 }
  43         }
  44
  45         return NULL;
  46 }
  47 EXPORT_SYMBOL_GPL(usb_of_get_child_node);
  48