include/linux/pci-pwrctrl.h

   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__ */