// 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(sizeof(*pdle), GFP_KERNEL);
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);
Codebase Browser
linux