// SPDX-License-Identifier: GPL-2.0-only/* * API for creating and destroying USB onboard platform devices * * Copyright (c) 2022, Google LLC */ #include <linux/device.h>#include <linux/export.h>#include <linux/kernel.h>#include <linux/list.h>#include <linux/of.h>#include <linux/of_platform.h>#include <linux/platform_device.h>#include <linux/usb.h>#include <linux/usb/hcd.h>#include <linux/usb/of.h>#include <linux/usb/onboard_dev.h> #include "onboard_usb_dev.h" struct pdev_list_entry {	struct platform_device *pdev;	struct list_head node;}; static bool of_is_onboard_usb_dev(struct device_node *np){	return !!of_match_node(onboard_dev_match, np);} /** * onboard_dev_create_pdevs -- create platform devices for onboard USB devices * @parent_hub	: parent hub to scan for connected onboard devices * @pdev_list	: list of onboard platform devices owned by the parent hub * * Creates a platform device for each supported onboard device that is connected * to the given parent hub. The platform device is in charge of initializing the * device (enable regulators, take the device out of reset, ...). For onboard * hubs, it can optionally control whether the device remains powered during * system suspend or not. * * To keep track of the platform devices they are added to a list that is owned * by the parent hub. * * Some background about the logic in this function, which can be a bit hard * to follow: * * Root hubs don't have dedicated device tree nodes, but use the node of their * HCD. The primary and secondary HCD are usually represented by a single DT * node. That means the root hubs of the primary and secondary HCD share the * same device tree node (the HCD node). As a result this function can be called * twice with the same DT node for root hubs. We only want to create a single * platform device for each physical onboard device, hence for root hubs the * loop is only executed for the root hub of the primary HCD. Since the function * scans through all child nodes it still creates pdevs for onboard devices * connected to the root hub of the secondary HCD if needed. * * Further there must be only one platform device for onboard hubs with a peer * hub (the hub is a single physical device). To achieve this two measures are * taken: pdevs for onboard hubs with a peer are only created when the function * is called on behalf of the parent hub that is connected to the primary HCD * (directly or through other hubs). For onboard hubs connected to root hubs * the function processes the nodes of both peers. A platform device is only * created if the peer hub doesn't have one already. */void onboard_dev_create_pdevs(struct usb_device *parent_hub, struct list_head *pdev_list){	int i;	struct usb_hcd *hcd = bus_to_hcd(parent_hub->bus);	struct device_node *np, *npc;	struct platform_device *pdev;	struct pdev_list_entry *pdle; 	if (!parent_hub->dev.of_node)		return; 	if (!parent_hub->parent && !usb_hcd_is_primary_hcd(hcd))		return; 	for (i = 1; i <= parent_hub->maxchild; i++) {		np = usb_of_get_device_node(parent_hub, i);		if (!np)			continue; 		if (!of_is_onboard_usb_dev(np))			goto node_put; 		npc = of_parse_phandle(np, "peer-hub", 0);		if (npc) {			if (!usb_hcd_is_primary_hcd(hcd)) {				of_node_put(npc);				goto node_put;			} 			pdev = of_find_device_by_node(npc);			of_node_put(npc); 			if (pdev) {				put_device(&pdev->dev);				goto node_put;			}		} 		pdev = of_platform_device_create(np, NULL, &parent_hub->dev);		if (!pdev) {			dev_err(&parent_hub->dev,				"failed to create platform device for onboard dev '%pOF'\n", np);			goto node_put;		} 		pdle = kzalloc_obj(*pdle);		if (!pdle) {			of_platform_device_destroy(&pdev->dev, NULL);			goto node_put;		} 		pdle->pdev = pdev;		list_add(&pdle->node, pdev_list); node_put:		of_node_put(np);	}}EXPORT_SYMBOL_GPL(onboard_dev_create_pdevs); /** * onboard_dev_destroy_pdevs -- free resources of onboard platform devices * @pdev_list	: list of onboard platform devices * * Destroys the platform devices in the given list and frees the memory associated * with the list entry. */void onboard_dev_destroy_pdevs(struct list_head *pdev_list){	struct pdev_list_entry *pdle, *tmp; 	list_for_each_entry_safe(pdle, tmp, pdev_list, node) {		list_del(&pdle->node);		of_platform_device_destroy(&pdle->pdev->dev, NULL);		kfree(pdle);	}}EXPORT_SYMBOL_GPL(onboard_dev_destroy_pdevs);