134 lines
3.3 KiB
C
134 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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* Copyright (C) 2017 Johan Hovold <johan@kernel.org>
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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_device_node() - get a USB device node
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* @hub: hub to which device is connected
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* @port1: one-based index of port
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*
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* Look up the node of a USB device given its parent hub device and one-based
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* 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_device_node(struct usb_device *hub, int port1)
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{
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struct device_node *node;
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u32 reg;
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for_each_child_of_node(hub->dev.of_node, node) {
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if (of_property_read_u32(node, "reg", ®))
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continue;
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if (reg == port1)
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return node;
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(usb_of_get_device_node);
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/**
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* usb_of_has_combined_node() - determine whether a device has a combined node
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* @udev: USB device
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*
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* Determine whether a USB device has a so called combined node which is
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* shared with its sole interface. This is the case if and only if the device
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* has a node and its decriptors report the following:
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*
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* 1) bDeviceClass is 0 or 9, and
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* 2) bNumConfigurations is 1, and
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* 3) bNumInterfaces is 1.
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*
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* Return: True iff the device has a device node and its descriptors match the
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* criteria for a combined node.
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*/
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bool usb_of_has_combined_node(struct usb_device *udev)
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{
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struct usb_device_descriptor *ddesc = &udev->descriptor;
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struct usb_config_descriptor *cdesc;
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if (!udev->dev.of_node)
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return false;
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switch (ddesc->bDeviceClass) {
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case USB_CLASS_PER_INTERFACE:
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case USB_CLASS_HUB:
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if (ddesc->bNumConfigurations == 1) {
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cdesc = &udev->config->desc;
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if (cdesc->bNumInterfaces == 1)
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return true;
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}
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}
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return false;
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}
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EXPORT_SYMBOL_GPL(usb_of_has_combined_node);
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/**
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* usb_of_get_interface_node() - get a USB interface node
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* @udev: USB device of interface
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* @config: configuration value
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* @ifnum: interface number
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*
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* Look up the node of a USB interface given its USB device, configuration
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* value and interface 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 *
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usb_of_get_interface_node(struct usb_device *udev, u8 config, u8 ifnum)
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{
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struct device_node *node;
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u32 reg[2];
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for_each_child_of_node(udev->dev.of_node, node) {
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if (of_property_read_u32_array(node, "reg", reg, 2))
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continue;
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if (reg[0] == ifnum && reg[1] == config)
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return node;
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(usb_of_get_interface_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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