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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2024 Linaro Ltd.
4 */
5
6#ifndef __PCI_PWRCTRL_H__
7#define __PCI_PWRCTRL_H__
8
9#include <linux/notifier.h>
10#include <linux/workqueue.h>
11
12struct device;
13struct device_link;
14
15/*
16 * This is a simple framework for solving the issue of PCI devices that require
17 * certain resources (regulators, GPIOs, clocks) to be enabled before the
18 * device can actually be detected on the PCI bus.
19 *
20 * The idea is to reuse the platform bus to populate OF nodes describing the
21 * PCI device and its resources, let these platform devices probe and enable
22 * relevant resources and then trigger a rescan of the PCI bus allowing for the
23 * same device (with a second associated struct device) to be registered with
24 * the PCI subsystem.
25 *
26 * To preserve a correct hierarchy for PCI power management and device reset,
27 * we create a device link between the power control platform device (parent)
28 * and the supplied PCI device (child).
29 */
30
31/**
32 * struct pci_pwrctrl - PCI device power control context.
33 * @dev: Address of the power controlling device.
34 *
35 * An object of this type must be allocated by the PCI power control device and
36 * passed to the pwrctrl subsystem to trigger a bus rescan and setup a device
37 * link with the device once it's up.
38 */
39struct pci_pwrctrl {
40 struct device *dev;
41
42 /* Private: don't use. */
43 struct notifier_block nb;
44 struct device_link *link;
45 struct work_struct work;
46};
47
48void pci_pwrctrl_init(struct pci_pwrctrl *pwrctrl, struct device *dev);
49int pci_pwrctrl_device_set_ready(struct pci_pwrctrl *pwrctrl);
50void pci_pwrctrl_device_unset_ready(struct pci_pwrctrl *pwrctrl);
51int devm_pci_pwrctrl_device_set_ready(struct device *dev,
52 struct pci_pwrctrl *pwrctrl);
53
54#endif /* __PCI_PWRCTRL_H__ */