drivers/usb/core/of.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * of.c         The helpers for hcd device tree support
   4  *
   5  * Copyright (C) 2016 Freescale Semiconductor, Inc.
   6  * Author: Peter Chen <peter.chen@freescale.com>
   7  */
   8
   9 #include <linux/of.h>
  10 #include <linux/of_platform.h>
  11 #include <linux/usb/of.h>
  12
  13 /**
  14  * usb_of_get_child_node - Find the device node match port number
  15  * @parent: the parent device node
  16  * @portnum: the port number which device is connecting
  17  *
  18  * Find the node from device tree according to its port number.
  19  *
  20  * Return: A pointer to the node with incremented refcount if found, or
  21  * %NULL otherwise.
  22  */
  23 struct device_node *usb_of_get_child_node(struct device_node *parent,
  24                                         int portnum)
  25 {
  26         struct device_node *node;
  27         u32 port;
  28
  29         for_each_child_of_node(parent, node) {
  30                 if (!of_property_read_u32(node, "reg", &port)) {
  31                         if (port == portnum)
  32                                 return node;
  33                 }
  34         }
  35
  36         return NULL;
  37 }
  38 EXPORT_SYMBOL_GPL(usb_of_get_child_node);
  39
  40 /**
  41  * usb_of_get_companion_dev - Find the companion device
  42  * @dev: the device pointer to find a companion
  43  *
  44  * Find the companion device from platform bus.
  45  *
  46  * Takes a reference to the returned struct device which needs to be dropped
  47  * after use.
  48  *
  49  * Return: On success, a pointer to the companion device, %NULL on failure.
  50  */
  51 struct device *usb_of_get_companion_dev(struct device *dev)
  52 {
  53         struct device_node *node;
  54         struct platform_device *pdev = NULL;
  55
  56         node = of_parse_phandle(dev->of_node, "companion", 0);
  57         if (node)
  58                 pdev = of_find_device_by_node(node);
  59
  60         of_node_put(node);
  61
  62         return pdev ? &pdev->dev : NULL;
  63 }
  64 EXPORT_SYMBOL_GPL(usb_of_get_companion_dev);