1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2024 Linaro Ltd.
4  */
5 
6 #ifndef __PCI_PWRCTL_H__
7 #define __PCI_PWRCTL_H__
8 
9 #include <linux/notifier.h>
10 #include <linux/workqueue.h>
11 
12 struct device;
13 struct 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_pwrctl - 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 pwrctl subsystem to trigger a bus rescan and setup a device
37  * link with the device once it's up.
38  */
39 struct pci_pwrctl {
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 
48 void pci_pwrctl_init(struct pci_pwrctl *pwrctl, struct device *dev);
49 int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl);
50 void pci_pwrctl_device_unset_ready(struct pci_pwrctl *pwrctl);
51 int devm_pci_pwrctl_device_set_ready(struct device *dev,
52 				     struct pci_pwrctl *pwrctl);
53 
54 #endif /* __PCI_PWRCTL_H__ */
55