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 * This program is free software: you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 of 10 * the License as published by the Free Software Foundation. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include <linux/of.h> 22 #include <linux/of_platform.h> 23 #include <linux/usb/of.h> 24 25 /** 26 * usb_of_get_child_node - Find the device node match port number 27 * @parent: the parent device node 28 * @portnum: the port number which device is connecting 29 * 30 * Find the node from device tree according to its port number. 31 * 32 * Return: A pointer to the node with incremented refcount if found, or 33 * %NULL otherwise. 34 */ 35 struct device_node *usb_of_get_child_node(struct device_node *parent, 36 int portnum) 37 { 38 struct device_node *node; 39 u32 port; 40 41 for_each_child_of_node(parent, node) { 42 if (!of_property_read_u32(node, "reg", &port)) { 43 if (port == portnum) 44 return node; 45 } 46 } 47 48 return NULL; 49 } 50 EXPORT_SYMBOL_GPL(usb_of_get_child_node); 51 52 /** 53 * usb_of_get_companion_dev - Find the companion device 54 * @dev: the device pointer to find a companion 55 * 56 * Find the companion device from platform bus. 57 * 58 * Takes a reference to the returned struct device which needs to be dropped 59 * after use. 60 * 61 * Return: On success, a pointer to the companion device, %NULL on failure. 62 */ 63 struct device *usb_of_get_companion_dev(struct device *dev) 64 { 65 struct device_node *node; 66 struct platform_device *pdev = NULL; 67 68 node = of_parse_phandle(dev->of_node, "companion", 0); 69 if (node) 70 pdev = of_find_device_by_node(node); 71 72 of_node_put(node); 73 74 return pdev ? &pdev->dev : NULL; 75 } 76 EXPORT_SYMBOL_GPL(usb_of_get_companion_dev); 77