forked from mirrors/linux
60a93cffcf
Document that the child-node lookup helper takes a reference to the device-tree node which needs to be dropped after use. Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
75 lines
2.1 KiB
C
75 lines
2.1 KiB
C
/*
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* of.c The helpers for hcd device tree support
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*
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* Copyright (C) 2016 Freescale Semiconductor, Inc.
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* Author: Peter Chen <peter.chen@freescale.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 of
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* the License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/usb/of.h>
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/**
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* usb_of_get_child_node - Find the device node match port number
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* @parent: the parent device node
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* @portnum: the port number which device is connecting
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*
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* Find the node from device tree according to its port number.
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*
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* Return: A pointer to the node with incremented refcount if found, or
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* %NULL otherwise.
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*/
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struct device_node *usb_of_get_child_node(struct device_node *parent,
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int portnum)
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{
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struct device_node *node;
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u32 port;
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for_each_child_of_node(parent, node) {
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if (!of_property_read_u32(node, "reg", &port)) {
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if (port == portnum)
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return node;
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}
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(usb_of_get_child_node);
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/**
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* usb_of_get_companion_dev - Find the companion device
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* @dev: the device pointer to find a companion
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*
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* Find the companion device from platform bus.
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*
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* Takes a reference to the returned struct device which needs to be dropped
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* after use.
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*
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* Return: On success, a pointer to the companion device, %NULL on failure.
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*/
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struct device *usb_of_get_companion_dev(struct device *dev)
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{
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struct device_node *node;
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struct platform_device *pdev = NULL;
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node = of_parse_phandle(dev->of_node, "companion", 0);
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if (node)
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pdev = of_find_device_by_node(node);
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of_node_put(node);
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return pdev ? &pdev->dev : NULL;
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}
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EXPORT_SYMBOL_GPL(usb_of_get_companion_dev);
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