| 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 | |
|---|
| 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_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 | */ |
|---|
| 39 | struct 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 | |
|---|
| 48 | void pci_pwrctrl_init(struct pci_pwrctrl *pwrctrl, struct device *dev); |
|---|
| 49 | int pci_pwrctrl_device_set_ready(struct pci_pwrctrl *pwrctrl); |
|---|
| 50 | void pci_pwrctrl_device_unset_ready(struct pci_pwrctrl *pwrctrl); |
|---|
| 51 | int devm_pci_pwrctrl_device_set_ready(struct device *dev, |
|---|
| 52 | struct pci_pwrctrl *pwrctrl); |
|---|
| 53 | |
|---|
| 54 | #endif /* __PCI_PWRCTRL_H__ */ |
|---|
| 55 | |
|---|
